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karimwassef
08/05/2015, 11:23 AM
I went scuba diving in Cancun last week and came back with a strong desire to replicate the large volume laminar flow I experienced around the coral reef. As I work up some ideas, I wanted to see if anyone else has attempted this successfully (or not).

Let me describe what it is and isn't.

Any pump or surge outlet is basically a pipe. 1", 2", ...12" it's still a pipe. The powerheads, even the ones with wide flow patterns still pull water locally and then thrust it through a channel, even a wide cone channel. I'm still calling that a pipe. So this project is explicitly not a pipe outlet.

Now let me describe what it is that I want to duplicate... Imagine that you're a sea fan on a rock. That rock is in the middle of a big tank of static water. The rock sits on a cart/dolly/roller on straight tracks. The roller moves forward and backwards on the tracks so that the complete motion takes about 4 seconds and moves about 12 inches in each direction. Now, from the coral's point of view, the entire mass of water around you has moved forward and back. There was no 'flow pattern'. Every bit of water moved around you in a straight line in the same direction with the only turbulence caused by interference with the coral itself. No shear action. No vortices. No turbulence.

It literally feels like inhaling and exhaling.

So- to do that in a tank (where the corals don't sit on rollers)... is ambitious, I think.

First thought is to look at a fictional completely sealed square pipe (like a sealed tank including the top), with a pipe connected to the left wall and another to the right wall. The pipes are connected to a massive piston (or reversible DC pump) and to each other. As the piston moves, the same volume of water enters one side as exits the other. The inlet and outlet need to be huge and the laminar effect is only emulated in the middle of the tank away from the inlet and outlet. Still feels like pipes close to the walls.

Second thought is using a laminar flow creator. This is a box with hundreds of plastic straws in parallel that helps create the smooth flow. One box at each end? That may convert 'pipe' flow to a uniform laminar flow. Still not very good and takes up a lot of space.

Third is a moving wall the size of a side panel - with pistons to move it back and forth. The opposite wall would have the same in the opposite direction. If they move together at the same rate, they should smoothly move the volume between them (assuming they're not moving too fast).

Has anyone tried these ideas? Different idea? to get to this goal.

karimwassef
08/05/2015, 11:44 AM
To be clear, I don't want to set up surface waves or standing waves by pushing flow and have it bounce back from the opposite wall. I want the entire volume to shift to the left and then to the right. No waves.

slief
08/05/2015, 12:19 PM
That's essentially what I have in my tank. Tunze's on the back wall all pushing towards the opposite end 8' away. The turn on and off constantly sending a surge that rushes across the length of the tank hits the wall 8' away and then bounces back towards the power heads.
It took some experimenting with the on/off interval to get it to work but it works well with no dead spots and a good back and forth motion that is very visible.

sleepydoc
08/05/2015, 01:40 PM
How does that work with your overflow?

slief
08/05/2015, 01:50 PM
How does that work with your overflow?

No issues for me at all. My tunze's concentrate most of the flow to the lower 2/3rds of the tank while my Sea Swirls on my return cover the upper level and face the Tunze's. I get a 1" rise and fall surge at the surface every few seconds but it doesn't impact my overflow noticeably and given that my tank is totally enclosed by drywall and there is a lid over the overflow, the sound isn't noticeable with the doors closed. I also don't use durso's or anything in my overflow. I let the water crash through it for maximum aeration. I also have a pair of 2" bulkheads in the bottom of it so flow is never an issue.

Bent
08/05/2015, 01:59 PM
I always thought it would be neat to have something that repeatedly drops something heavy in the water and lifts it out.

callsign4223
08/05/2015, 03:14 PM
I always thought it would be neat to have something that repeatedly drops something heavy in the water and lifts it out.

You wouldn't need to drop something heavy into the tank, you could just push something buoyant down. I'm picturing something like a boat fender being pushed up and down by slow reciprocating motor.

Bent
08/05/2015, 03:52 PM
You wouldn't need to drop something heavy into the tank, you could just push something buoyant down. I'm picturing something like a boat fender being pushed up and down by slow reciprocating motor.

Yeah that's true. Just something to displace the water.

ericarenee
08/05/2015, 04:05 PM
You wouldn't need to drop something heavy into the tank, you could just push something buoyant down. I'm picturing something like a boat fender being pushed up and down by slow reciprocating motor.

Newport Aquarium up near Cincy has a Wave Aquarium To mimic a storm in the ocean floor there are some fish in there but i forget what kind. The tank is Prob 30 feet across 15 feet tall and not sure how deep 6-8 feet or so..

On each end there is Hydraulic cylinder that works like this.. One pushes down the other pulls up..Pulling and pushing the water thru slots . The Floats looked to me like plastic of some kind riding on some type of guide..

karimwassef
08/05/2015, 05:18 PM
Thanks erica. I'll look into it.

I don't want a wave bouncing and reflecting back. This is not a wave machine.

If done right, the surface can be completely still. The whole volume moves forward and back.

If I'm making waves, then I don't have the laminar straight flow I'm looking for.

slief
08/05/2015, 07:43 PM
Thanks erica. I'll look into it.

I don't want a wave bouncing and reflecting back. This is not a wave machine.

If done right, the surface can be completely still. The whole volume moves forward and back.

If I'm making waves, then I don't have the laminar straight flow I'm looking for.

And just what do you think will happen when the "whole volume" of water moves one direction in a closed space and the volume of water hits the wall? You don't think this will cause a wave?? I can guarantee you it will. The water that hits the vertical surface has to go some place when there is water behind it pushing the same direction. It will hit the wall and go up and down which will create a rise in the waters surface.

Edit: By the way, I'm not trying to be condescending. Just pointing out that if the flow will create waves.

laverda
08/05/2015, 07:52 PM
What you want is exactly what wave boxes do when set up properly. Tunze and Wave2K are 2 examples. They gently move all the water in the tank uniformly back and forth. They work best in longer tanks then square tanks. Not really achievable with pumps alone.

Gorgok
08/05/2015, 07:59 PM
Even if you did the amazing of putting the rockwork on a rack and dragging that back and forth you will end up just creating waves without the near infinity of the ocean to dissipate the return...

You could probably dissipate it some with a shallow ramp to an overflow at each end of a tank, but they would probably have to be as long as the tank or more... Even then some will come back as a wave.

ericarenee
08/05/2015, 07:59 PM
Thanks erica. I'll look into it.

I don't want a wave bouncing and reflecting back. This is not a wave machine.

If done right, the surface can be completely still. The whole volume moves forward and back.

If I'm making waves, then I don't have the laminar straight flow I'm looking for.

I think i explained that wrong..
BUT What you are talking about could be maybe created With a Gate valve like configuration on each end.
This will take a very long tank.

So 10 foot tank. With 5 foot middle second 1.5 feet on each end.. Each end of the 5 foot section Have slots cut from right above the sand bed to 6 inches below the water .. Would have to experiment To get the right size slots and where to position them. I think horizontal would be best..

The top of the end boxes might need to be somewhat sealed at the top or the gate structure would need to seal the water from getting behind it. when it goes back it will push water up .. So maybe the top of the baffle would need to be a bit short so the back stroke of the gate would push water over top

Then have a hinge plate that can open and close.when open it will allow (kinda pull water into the 1.5 foot area. it would have to be timed with the other side Closing pushing its 1.5 foot area empty (or somewhat empty prob does not need to seal) ... This would cause the gentle wave your talking about ..
The one at the Aquarium.. Goes back and then up with Hydraulics if i remember right.. I caused the water to make waves at the surface and you could see the fish still able to swim in the lower wake...

You could control the speed and wake in the tank depending on the speed and sync of the Gates....

Just my Theory... If had time and energy to put into it i would test this on a smaller scale....
------------------------------------ off topic sorry---------------------------------
I Have a badly messed up arm and Limit what i do by Priority... its 1 hour working 6 hours on the couch with ice or 3 hours sleeping from pain meds..

----------------------Not Complain there are people far worse---------------

karimwassef
08/05/2015, 08:51 PM
Thanks for the feedback. Erica and Gorgok, I see what you're saying. I was thinking of an 8 ft tank with 1 foot on each end dedicated to creating the translating water motion. Basically, I'd end up with a 6 foot viewable area and two feet of motorized areas. I hadn't thought of using slanted wall. I agree that the middle 3ft would be closest to the effect I'm thinking of. That's why this is so difficult and very different from a pump's flow.

Slief - If I was pushing water from one direction and hitting a solid wall, I'd get a wave. I'm not talking about that, I'm talking about both side walls moving so the volume shifts - translates.

I find the biggest challenge here on the opposite end of tank - far from where water is being pushed.

Let's say that I have a thousand tiny pumps on the left wall that take water from an external tank and inject it to the right. At the opposite end, that water needs to slow into another thousand pumps back up to the reservoir at the same rate. It can't have an overflow or a solid wall. The water coming in must be equal to the water exiting to avoid a wave.

karimwassef
08/05/2015, 08:57 PM
My example of rockwork on a rolling frame was to explain what the coral experiences in this kind of motion. The actual movement of water away from the rock and coral would not be laminar, but the coral would experience the sensation of a moving ocean, at least for one cycle.

The bigger the tank, the more cycles that could be performed before the bounce back from the tank walls would disrupt the water at the source of the motion.

I'm only using this to define what I want the coral to experience.

karimwassef
08/05/2015, 09:03 PM
Building on erica's idea...

So, how about an 8ft tank with false walls (1ft in) at each end and a sealed top connected to a DC pump and each other. Horizontal slits cut into the false wall close enough so that they simulate laminar flow. The inside of the wall could also have little ledges above and below the slits to extend the effective depth of the slits...

Now, the pump take water from one side and pumps it to the other side at the same rate (slow ramp, slow ramp down) and then reverses?

That sounds like it would do it?

karimwassef
08/05/2015, 09:07 PM
When I say slow, I mean the overall rate at a point feels slow? But this would be a beast of a DC pump to move a 2' x 2' x 1' volume of water in 4 seconds... 27000 gph... Or split the feed to 5 DC pumps.

slief
08/05/2015, 10:15 PM
Slief - If I was pushing water from one direction and hitting a solid wall, I'd get a wave. I'm not talking about that, I'm talking about both side walls moving so the volume shifts - translates.



I get what you are saying but lets assume you have a pump at either end. You would still be staggering flow to create the back and forth motion. When one pump fires up and displaces a 2'x2'x1' volume of water, kinetic energy will will cause the water on the other end of the tank to rise and fall even if to a minor degree. You already noted that you will need a pretty high amount of flow to create your desired flow. There will be a "ripple effect" from the burst of flow or even ramp of flow and having two pumps at opposite sides. The shifting the flow. The back and forth between the two pumps will have an impact on the surface just the same as having a single pump or pumps at one end.

karimwassef
08/05/2015, 10:30 PM
That's why I said the biggest difficulty is extracting water from the right wall (sink), not pumping it in at the left (injection) wall.

I also don't see this working with two pumps. The same flow entering must be exiting.

As I pump water at the left wall, it begins a flow from left to right. Simultaneously, I'm pumping water out on the right side, pulling water from left to right also. The effect is a sideways shift.

No system is perfect and in a real tank, there will be waves and ripples. I'm not saying that's bad. I'm just saying that waves are not the goal. Not traveling or standing waves.

Most water movers are "wave machines". I want to be clear that this is not a wave machine. Incidental waves will occur, but the point is to move a laminar block of water. That's different.

Gorgok
08/06/2015, 02:54 AM
Thinking on this further the laminar flow fountain stuff comes to mind as a possibility if you are indeed willing to lose ~2 feet of tank space... Not with straws because they will clog too fast, but a compromise of some size/length you can live with and 2 decent pressure pumps. One intakes from the left 'straw box' and outputs in the right, the other the reverse. Only one can be on at any point.

But for them to work i think you must have enough pressure in the box, and back pressure in the tubes, for it to fill the whole thing instead of just running out the first holes it can... not sure how big a pump like that is on a ~2' x 2' area.

karimwassef
08/06/2015, 06:59 AM
I started with the best idealized case and I'll probably walk backup an acceptable solution that is just good enough. 2' out of an 8' tank would yield excellent results, but maybe 3" is good enough?

Also the rockwork will interfere. So unless I change my rock to open water volume ratio, I can reduce the box a little from the edges.

Maybe two boxes, 18" x 24" x 3" made of 1/2" acrylic with the slit face doubled up to 1". Horizontal 1/4" slits separated by 1/4"? The slits would be 1" deep, 1/4" high and 1/4" apart. Inlet of two 2" PVC pipes from the top.

Painted to minimize internal fouling...

I agree the key here is pressure so the slits share more equally too.

This may be possible.

Wish I had modeling software to optimize some of the dimensions.

karimwassef
08/06/2015, 07:04 AM
1/4" may suck some thin fish and shrimp in... Hmmm that's not good.

The greater the aspect ratio of the slit cross-section, the more laminar the flow. So 1/4" x 1" is 4:1, maybe 1/8" x 1.5" to get a 12:1 and double up on the slit count?

I'm going to need a really good machinist or milling CNC.

karimwassef
08/06/2015, 07:11 AM
At 27000 gph, the linear flow rate through a slit would be 8" a second... Enough for a shrimp to not get sucked in?

saf1
08/06/2015, 07:47 AM
The issue you have is the size of your environment (e.g. aquarium) you are working with. I know what you are trying to do as I am also an active diver. However, I've come to the conclusion that it really isn't possible to replicate some of these things just due to the size of our tanks.

Personally I think Slief's method will get you the closest. I am doing something similar to what he describes on my 40 breeder with a pair of RW-4's. In your case just don't run any surface power heads or sea swirls (love those things btw - great devices) so all the flow is in the lower 2/3rd's of the tank. You will need to adjust duration and probably left, right, and height placement but I bet you would get what you want that way.

One other thing I'd consider is how your tank is manufactured. Standard over the counter tanks are not really built with surge or waves in mind. That sort of stuff is going to require some additional engineering to support the tank walls. May not be applicable to what you are considering but figured I'd throw that out there.

ericarenee
08/06/2015, 09:27 AM
I am not convinced that the two pump method will work. To me it seems like you would need 4 pumps using pumps

one in each direction on each end with some type of valve similar t check valve and a Volute of some type.. Hard to describe.

So the pump on the right pulls water out and into the chamber on the left . While the pump on the left is pushing that pulled water into the tank across the right of the tank.. Then those two shut off and close the Above mentioned valve..

Then the second pump on the right push water into the tank while the second pump on the left pulls waster out and pushes it thru a 2nd pipe into the right.. Kinda like a Double closed loop on timers.....

Thinking about this building a baffle or some type of valve to push the water into the slots right Might be the best solution over some mechanical swing gate as i originally talked about.... The one i seen in action however was a gate... But its been 15 years since i at the aquarium . that tank might not have lasted long term. Do not know if its still there or not..

In theory either system will work . But likely to have design kinks to work out.. Slot sizes Baffels design pump and plumbing.. .

The pumps will have to go in bulkheads at the end of the tank next to each other may make the above mentioned valves not needed when i picture this in my head... A Controller with soft on and off pumps i think will be required....


---------------------------------- MIND CHANGE----------------

TWO Big HUGE PUMPS Behind the tank in two closed loops Of Course the pumps will be connected to bulklheads on the far end of the glass NOT AT THE SLOT Wall.. one in each direction on a timer may eliminate the need for 4 pumps.. I do think check valves will be needed to stop the water from back circulation thru the off pump.during its down cycle

karimwassef
08/06/2015, 09:46 AM
I have a large surge already - dual 20g surges that run for 10seconds.

I also run two WP-60s on opposite ends of my eight foot tank. I have standing waves and tremendous motion on the surface and depth.

I also have two opposing MP40s that do the same behind the rockwork too.

karimwassef
08/06/2015, 09:52 AM
I was thinking of a reversible DC pump that can do it both ways.

They don't work as well in reverse, so I was thinking of two pumps in series and in opposite directions with opposite polarities. The idea is that one pump is always running in its forward direction. The second is just providing more pressure to make up for the impedance it is creating in-line.

Efficiency isn't top of list right now - a dual bi directional reversible inline pump configuration should do it. The two boxes, pipes and pumps are basically a closed loop massive power head that sucks on one wall and pumps in at the other through laminarizing plates.

Is laminarizing a real word ??

ericarenee
08/06/2015, 10:52 AM
I was thinking of a reversible DC pump that can do it both ways.

They don't work as well in reverse, so I was thinking of two pumps in series and in opposite directions with opposite polarities. The idea is that one pump is always running in its forward direction. The second is just providing more pressure to make up for the impedance it is creating in-line.

Efficiency isn't top of list right now - a dual bi directional reversible inline pump configuration should do it. The two boxes, pipes and pumps are basically a closed loop massive power head that sucks on one wall and pumps in at the other through laminarizing plates.

Is laminarizing a real word ??

if not i will submit it to wiki ......

Yea i get the concept. Maybe 1 pump with some type of electric valve.......

it for sure would need to be a dc pump. turning ac motors on and off will drastically shorten there life

I have seen your Surge system and looked it over a few times... Thought about such a project I could actually put the surge tanks in the Attic above the aquarium... Our ATTIC is big enough to put 3 bedrooms up there and has a stairway thou Tiny . 88 year old house..

Anyway i think a Test tank is in order....Lets see the Build thread... would be awesome to have NO HARDWARE inside the tank....

Today i am working on Rebuilding my Sump/ Aquarium room.. Its ugly dark and more ugly.. Going to re arrange the plumbing and tidy it all up ...then add a new system of smaller tanks that i have just sitting down there...
When i get my 3d bottom and back insert done for my Display i will need a place to house everyone for a few weeks...... In a smaller tank i will have to separate the tangs as they only tolerate each other in the big tank

karimwassef
08/06/2015, 12:24 PM
Sounds like a lot of elbow grease!

Wish there were enough reef keepers in proximity to take these projects on as a barn-raising and do it in a weekend.

I might start by retrofitting my surge outlets to test the concept. Gravity fed from 36" isn't a lot of pressure but I might learn something from it.

Have you seen my surge vids? Maybe I need to make new ones now that my tank is stocked.

saf1
08/06/2015, 12:56 PM
Still think you are over engineering or complicating it. DC / Variable pumps have been created for a reason. Might be worth while breaking out excel and seeing what sort of wave patterns you could come up with. Still might be able to do what you want by height placement and timing / control.

Based on your sig you have a large tank so it is probably built to handle surge and/or waves. I know part of the fun of the hobby is this sort of thing so will be interesting to see what you come up with.

ericarenee
08/06/2015, 01:00 PM
Sounds like a lot of elbow grease!

Wish there were enough reef keepers in proximity to take these projects on as a barn-raising and do it in a weekend.

I might start by retrofitting my surge outlets to test the concept. Gravity fed from 36" isn't a lot of pressure but I might learn something from it.

Have you seen my surge vids? Maybe I need to make new ones now that my tank is stocked.

Yes i seen them.... Very nice....

I think the benefit of this is NO Air bubbles and it would be a steady swaying ..
Yea would be a kewl project for like minded people close together and a Garage....


I Worked most my life in Construction (Degree in construction management). But now I Do renovations on historic homes. Where i work we have
a License plumber
a framer
a trim carpenter
a hvac guy..
and so on. then there is
ME AND One of the other guys. that has done a bit of everything.. When we hit a snag that is way out there. We will all get together on the project and often in minutes or a few Hours its Solved and We move foreword...
a Great team to work with ..... I have worked off some of the worse drawing in the world..

Anyway ... i can watch you build it from here and Point out your mistakes. (MY BEST ASSET) ...... :rollface:

KafudaFish
08/06/2015, 01:07 PM
Maybe hire this guy:

<iframe width="420" height="315" src="https://www.youtube.com/embed/8JVVEgx62oc" frameborder="0" allowfullscreen></iframe>

Though it is silly I think the video has possibilities. This video maybe better suited to your idea though:

<iframe width="560" height="315" src="https://www.youtube.com/embed/-m_VDE-BSgc" frameborder="0" allowfullscreen></iframe>

karimwassef
08/06/2015, 04:31 PM
... This is really not about waves. I have monster waves already.

I may have to draw it out since I'm failing at explaining how this is different from a wave.

karimwassef
08/06/2015, 04:32 PM
I'm building two more actuated surges. I'll include the DIY of the valves from PVC.

I'm hoping to make these new actuated valves adjustable instead of just on - off. It needs a processor, but I think I can DIY that too.

Bent
08/06/2015, 04:53 PM
Maybe hire this guy:

<iframe width="420" height="315" src="https://www.youtube.com/embed/8JVVEgx62oc" frameborder="0" allowfullscreen></iframe>

Though it is silly I think the video has possibilities. This video maybe better suited to your idea though:

<iframe width="560" height="315" src="https://www.youtube.com/embed/-m_VDE-BSgc" frameborder="0" allowfullscreen></iframe>

Is it weird that I put this on loop and let this dudes voice put me to sleep last night?

ericarenee
08/06/2015, 05:10 PM
... This is really not about waves. I have monster waves already.

I may have to draw it out since I'm failing at explaining how this is different from a wave.

I get it ..... I think its kewl................... Build two ...

Erica says she wants one toooo....Girls know nothing about this kinda mechanical stuff....:thumbsup:

ericarenee
08/06/2015, 05:12 PM
Is it weird that I put this on loop and let this dudes voice put me to sleep last night?

Is it weird that i think you are weird for even wondering rather or not you are weird for watching this weird voice while trying to weirdly fall a sleep...

JamesHolt
08/06/2015, 08:18 PM
8' tank
1' each end divided like this
http://i1323.photobucket.com/albums/u595/druknar/surge_zpsr4yjmkca.png
Seal the top on each side..
Come out the back with 6" pvc, connecting both ends together (1 piece)
off of one of the pvc 90's mount cylinder, through pvc 90 with cylinder shaft inside pvc.. attach a uhmw, plastic piston to shaft end,, this will be inside the pvc that goes from one side to the other..
When the cylinder moves, the piston will push water into one side while pulling from the other... one side will move a tad more due to the cylinder rod taking up space...
the dividers will direct the flow in a mostly straight line..

I could draw this up in CAD, but I am still learning it and am very slow..

You could downsize this for a smaller tank, and also use 2 rodless cylinders piggybacked to eliminate the connecting pvc..
On a rodless cylinder the piston free floats in the tube, but is magneticaly coupled to the driver,, makes it nice and compact..

do a 20 gallon long and use 2" stuff,, should be able to get a nice push in each direction...

karimwassef
08/06/2015, 08:20 PM
If you're reading this, you're probably weird enough to know you're weird.

Erica - you sound like you're pretty good with mechanical stuff- you're a carpenter! How much more hands on can one be?

Anyways - my actuators are very simple devices. The biggest trick is knowing the right size of standard pipes and fittings that work together.

karimwassef
08/06/2015, 08:24 PM
James. That sounds like it with a piston instead of a pump. I get the flow- but maybe draw up the piston mechanics?

I'm assuming this is like a massive powered syringe?

JamesHolt
08/06/2015, 08:27 PM
Yes,, the piston would be inside the tube running from side to side,, when it moves the water follows.
Just like a massive syringe, but with two ends

karimwassef
08/06/2015, 08:31 PM
How do you maintain the seal? Is it a DIY Or can you buy it?

JamesHolt
08/06/2015, 08:36 PM
Quickey MSPaint sketch..http://i1323.photobucket.com/albums/u595/druknar/Tank_zpsw3boekpn.png

karimwassef
08/06/2015, 08:43 PM
Thanks. How do you maintain the piston seal to the external actuator?

I would use the PVC extenders that I use for my surge actuators but this is a pressure application ... So that's a little concerning

<a href="http://s1062.photobucket.com/user/karimwassef/media/EA28999B-01E1-4283-B16E-0449CBF77B03.png_zpsxdhdfzcx.jpeg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/EA28999B-01E1-4283-B16E-0449CBF77B03.png_zpsxdhdfzcx.jpeg" border="0" alt=" photo EA28999B-01E1-4283-B16E-0449CBF77B03.png_zpsxdhdfzcx.jpeg"/></a>

pisanoal
08/06/2015, 08:49 PM
... This is really not about waves. I have monster waves already.

I may have to draw it out since I'm failing at explaining how this is different from a wave.

I'm confused how it's not a wave. The ocean surge that you were experiencing IS a wave. That's what causes it.

As to your idea, I would think a couple of DC pumps on either side switched on and off would work well enough to replicate what the corals see. If you are talking about visuals then of course it's much more complicated

karimwassef
08/06/2015, 09:48 PM
<a href="http://s1062.photobucket.com/user/karimwassef/media/1_zpsxcx18je5.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/1_zpsxcx18je5.jpg" border="0" alt=" photo 1_zpsxcx18je5.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/2_zpszaofc0ch.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/2_zpszaofc0ch.jpg" border="0" alt=" photo 2_zpszaofc0ch.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/3_zps4ejfftc5.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/3_zps4ejfftc5.jpg" border="0" alt=" photo 3_zps4ejfftc5.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/4_zps3csurgib.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/4_zps3csurgib.jpg" border="0" alt=" photo 4_zps3csurgib.jpg"/></a>

karimwassef
08/06/2015, 09:49 PM
Not perfect or complete but I hope it shows the differences.

JamesHolt
08/06/2015, 11:45 PM
for the seal on the cylinder shaft you would need a piece made with cup seals and o-ring in it
for the piston it would just need to be a close fit or use an o-ring

ericarenee
08/07/2015, 02:22 PM
If you're reading this, you're probably weird enough to know you're weird.

Erica - you sound like you're pretty good with mechanical stuff- you're a carpenter! How much more hands on can one be?

Anyways - my actuators are very simple devices. The biggest trick is knowing the right size of standard pipes and fittings that work together.

Thanks. yea i have always liked to tinker with things.. And to think i actually was planing attending pre med school (fathers idea) . But was just not me...

Quickey MSPaint sketch..http://i1323.photobucket.com/albums/u595/druknar/Tank_zpsw3boekpn.png

I Actually think this may be the best idea..
I say that because if you get the seals right it has the least moving parts . Moving parts is always the weak point of any Design..... would also be easiest to actually test and mock up in a environment your not worried about water on the floor....

karimwassef
08/07/2015, 02:57 PM
I'll mock it up, but the problem is volume.

Even in a 6" pipe, the volume of water moved is very small unless the piston stroke is very long.

So, with a foot of stroke, the volume moved is under 2gal. That pretty big in a 10gal tank, so good for proof of concept. But in a 400gal display, it's a puff ...

karimwassef
08/07/2015, 03:02 PM
The displacement piping actually needs to be a sealed tank.

Say, 24" x 24" x 18" with a 6" piston plunger. That's 24x24x12 water displaced ~ 30gal.

If I get that much movement (all 12") in 10 seconds, we're in the 11,000 gph range.

It's half of the target above, but may be feasible.

karimwassef
08/07/2015, 03:09 PM
It'll take a bunch on actuators to push that hard, that fast. Any hydrodynamics gurus around who can calculate how much force would be needed to move such a piston? It needs to move the volume through 12' of 2" piping and then two laminarizing boxes.

The boxes will create the most back pressure with 1/8" x 24" slits that are 1" deep... 96 slits total. That's per box, one inlet, the other outlets. Yikes

ericarenee
08/07/2015, 03:39 PM
I'll mock it up, but the problem is volume.

Even in a 6" pipe, the volume of water moved is very small unless the piston stroke is very long.

So, with a foot of stroke, the volume moved is under 2gal. That pretty big in a 10gal tank, so good for proof of concept. But in a 400gal display, it's a puff ...

The displacement piping actually needs to be a sealed tank.

Say, 24" x 24" x 18" with a 6" piston plunger. That's 24x24x12 water displaced ~ 30gal.

If I get that much movement (all 12") in 10 seconds, we're in the 11,000 gph range.

It's half of the target above, but may be feasible.

I see what you are saying..
The pipe would need to be prob 12 inches or equal to the slots in the plate. . of course the number of slots and size would have be experimented with in relation to the amount / type of water volume.....

The design has potential because it pushes and pulls the exact same water amount with would create the perfect under current without as much disturbance on the surface.....

But .. but but. yea i know there is always that Terrible small word...

Your right . it would work on a small scale. To scale this up you would have to have add more piston / Plunger valves.

For a tank that is 10x10 that would be 100 sq in per 1 Liner inch to move its whole volume you would need a pipe in equal diameter... The plate will reduce that need some maybe even half.. so that would be 50 inch of water Your piston / pipe would have to equal that .
Would take more then 1 ...

If not you would only get very tiny motion
Ideally the shorter the piston stroke the better (for lack of better terms). So for a 8 foot tank you might need two 12 or 14 inch piston assemblies with a near complete aquarium travel time.. To get a sustainable motion in either
direction.

karimwassef
08/07/2015, 03:47 PM
Lot of interdependent variables. Short piston means much large area to get the same volume... And the more force to squeeze against the larger area.

Come on... I know you fluid dynamics engineers are out there. Don't make me open my old textbooks.

ericarenee
08/07/2015, 05:16 PM
Lot of interdependent variables. Short piston means much large area to get the same volume... And the more force to squeeze against the larger area.

Come on... I know you fluid dynamics engineers are out there. Don't make me open my old textbooks.

1+

I know the problems . But do not know how to Calculate the solution without building and testing.. Its not wood and Metal.... :fun4:

JamesHolt
08/07/2015, 06:45 PM
Thought more on this idea this morning,,, pushing the water with cylinders would work good on a small scale,, but on a large scale, say over 100g tank the power consumption and support equipment needed would be costly..

Would be better to do like this
Still use the slotted dividers
Still seal the ends off..
Use two large AC pumps ,, for their quick ramp-up

Etch-a-Sketch below
http://i1323.photobucket.com/albums/u595/druknar/Tank2_zpsvmfvnotk.png

karimwassef
08/07/2015, 07:36 PM
That's were we were before but we were doing reversible DC pumps pointing in opposite directions and in series.

karimwassef
08/07/2015, 07:38 PM
I don't trust one way valves and the water is just as likely to go in a circle in the loop between the pumps as go in the big loop. That's especially true if the impedance of the big loop is high due to the slots.

JamesHolt
08/07/2015, 09:12 PM
Didnt mean to imply it was a one way valve..Just put "check" there as a generic term
For speed they would be to slow..
Pneumatic driven ball/disc valves or Pinch valves would be better.. I have used them as big as 24"
I dont remember ever using a pinch valve large than 6"..
Ideally you would have both pumps running constantly and just pop the valve as needed..

Got any pics of the surge setup you are using, may be able to use it, and just change the way it dumps in...

Are you just wondering about this or is this something you are really going to try...

karimwassef
08/07/2015, 11:08 PM
I have a 400gal with surge now. I added powerheads too.

I can move massive volumes of water.

But when I dive, the motion is completely different.

With a maturing stocked tank, I don't have the option to do this perfectly. So, I plan to learn as much as possible and establish proof of concept. I'll do it right on my next build.

This is how I developed my current tank's surge.

For my current tank, I'll have to retrofit my setup as best as I can. That's the goal.

karimwassef
08/07/2015, 11:09 PM
It's on my main build thread, but here's my engineering drawing

<a href="http://s1062.photobucket.com/user/karimwassef/media/2015view2_zps8uyarupv.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/2015view2_zps8uyarupv.jpg" border="0" alt=" photo 2015view2_zps8uyarupv.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/2015view1_zpsw2xbuw3k.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/2015view1_zpsw2xbuw3k.jpg" border="0" alt=" photo 2015view1_zpsw2xbuw3k.jpg"/></a>

And here are some pics

<a href="http://s1062.photobucket.com/user/karimwassef/media/55D6D60A-5593-4749-8EEF-E50A6B38052A_zpso4ixwwat.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/55D6D60A-5593-4749-8EEF-E50A6B38052A_zpso4ixwwat.jpg" border="0" alt=" photo 55D6D60A-5593-4749-8EEF-E50A6B38052A_zpso4ixwwat.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/0340EEC7-4A5B-40DF-A428-95FF27F8F32A_zpslwpa0sn7.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/0340EEC7-4A5B-40DF-A428-95FF27F8F32A_zpslwpa0sn7.jpg" border="0" alt=" photo 0340EEC7-4A5B-40DF-A428-95FF27F8F32A_zpslwpa0sn7.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/74E799A6-59B9-4CCE-90DA-30AFF48D0554_zpsty4m3yrf.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/74E799A6-59B9-4CCE-90DA-30AFF48D0554_zpsty4m3yrf.jpg" border="0" alt=" photo 74E799A6-59B9-4CCE-90DA-30AFF48D0554_zpsty4m3yrf.jpg"/></a>

JamesHolt
08/07/2015, 11:51 PM
Thanks for the pics,, I have a different idea, need to think on it a bit..
I have an old 55 I am not using, I may mock something up this weekend

karimwassef
08/08/2015, 12:00 AM
I don't think I can push the surge output through a laminarizing box.

The box needs high pressure. A surge is low pressure, high volume.

karimwassef
08/08/2015, 12:12 AM
This could be achieved with one pump with very high pressure output.

<a href="http://s1062.photobucket.com/user/karimwassef/media/Mobile%20Uploads/0F9F3351-4CA9-416E-9245-72D1D2F6B458_zpswgu1x93o.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/Mobile%20Uploads/0F9F3351-4CA9-416E-9245-72D1D2F6B458_zpswgu1x93o.jpg" border="0" alt=" photo 0F9F3351-4CA9-416E-9245-72D1D2F6B458_zpswgu1x93o.jpg"/></a>

The two ends each go to a box. The middle in a one directional pressure pump. The four valves are synchronized A-A and B-B. With the A on and B off, flow is to the right. With the opposite, flow is to the left.

The transition will be wasteful since the connection loops around the pump will carry the flow. A DC pump could be synchronized to ramp down to zero so the switching can be performed without flow and without loss.

karimwassef
08/08/2015, 12:16 AM
I don't know of any massive flow (20k gph) @ high pressure (20ft) reef capable DC pumps?

DC Pool pumps ?

Could also turn the AC pump off, but with continuous repetition, it would be short lived?

http://www.jandy.com/~/media/zodiac/global/downloads/sa/sa6220.pdf

karimwassef
08/08/2015, 12:32 AM
Little more research on this... The loops can be condensed into two three way actuated valves like this

http://www.valworx.com/product/electric-actuated-3-way-l-valve-pvcepdm-2-115-240v/electric-actuated-pvc-3-way-ball-valves-l-port-115v-240v?gclid=CIPMj6_umMcCFQYvaQod3f8J5g

<a href="http://s1062.photobucket.com/user/karimwassef/media/Mobile%20Uploads/7682D645-11F4-4970-A7BC-40B01BB62D20_zpsycypknrs.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/Mobile%20Uploads/7682D645-11F4-4970-A7BC-40B01BB62D20_zpsycypknrs.jpg" border="0" alt=" photo 7682D645-11F4-4970-A7BC-40B01BB62D20_zpsycypknrs.jpg"/></a>

Bent
08/08/2015, 01:03 AM
Here's an idea?

What would be wrong with using an air compressor and using it to force a volume of water from one spot to another?

You could even adjust the psi to the desired output, I can't imagine it taking much. Hook up an instant open solenoid and whamo.

jake2045
08/08/2015, 04:58 AM
What about two pneumatic pistons on either end of the box timed to push down/up and reed valves to control the intake and outlet. The stroke would have to be 2/3 the tanks depth but while one side was pushing down the other side would be filling with the same volume of water being push out.

karimwassef
08/08/2015, 08:12 AM
Bent- the air compressor could be a tad loud :)

That's kept me from considering pneumatic options. I guess the actuated piston we were talking about before could be pneumatic. I'm not sure how to set it up where the compressed air directly displaces water to create the motion.

karimwassef
08/08/2015, 08:20 AM
Jake - the up/down motion of the boxes would push the water horizontally (sideways), but I think it would also create a wave that's vertical (up-down).

Here's what I expect would happen- So if you push a box down on one side, the water under the box has to get out of way. It will go up and sideways. Depending on the speed, a lot of it would go up against the plunging box and create a big wave that travels sideways. The one on the right would be creating a sink or a hole as you pull it up, that will pull the surface water down and to the right. The up-wave traveling to the right and the down-wave traveling to the left would meet in the middle. They would cancel and the net will be a shift of the water volume, but it wouldn't be laminar. It would come with a big wave.

Maybe that's ok depending on the rate of the plungers. But I think to move a lot of water sideways, you'll also move a lot of water up and down?

karimwassef
08/08/2015, 08:41 AM
This brings up a good point that I think was part of the confusion in the beginning and Gorgok kind of explained it a bit.

When snorkeling, I'm floating at the water surface. The water does move in a wave, and this wave is moving me forward and backward a lot, but it's barely visible on the surface. It's not moving me up and down very much. The reason is the size of the wave and the 'tank' I'm in. The wave is 20 feet long but maybe 6 inches high over the water. Most of the wave is the 12 feet you can't see under the water. It also runs for a mile sideways....The point is that this wave is massive but barely visible because of how it is spread.

For a little snorkeler or coral, for the 10ft of space I'm swishing around in, I don't see or feel a wave. Locally, it's just a tiny little fraction of the real wave and it is very smooth and laminar. All other motions are spread so thin that you don't feel them. Only the forward-backward flow is felt and it is intense.

Why does it matter?

Watching the corals - it's as if they're breathing as they or their polyps are exposed to fresh water from opposing directions with a few seconds. It literally feels like a smooth, giant inhale-exhale with no turbulence or whipping around.

In a reef tank, with pumps, surges and powerheads, the scale would be a few mms of space where that's duplicated - instead of feet of flow. The only way to replicate the natural flow is to use a wave machine in a massive pool, or use an artificial means of creating laminar flow.

It's the same idea engineers use to mock up what a car would experience on the road in a tiny little test chamber. You create an artificial system to emulate the natural and real world.

karimwassef
08/08/2015, 11:07 AM
Some bad news... Working through the laminar flow math (Reynold's number, hydraulic diameter, entrance length), I come up with these formulas and results
With
speed v=4in/s
slit opening t=1/8"
Re = 1389 v * t = 694 (this needs to be less than 2100, so good here)
Le = 167 * v * t2 = 10"

So for this to work, the slits can't be 1" deep, they need to be 10" deep!

Making the slits bigger makes it worse. At less than 1/8", the back pressure goes higher. Might be an option, but discounting it for now. Making a deeper slit (2", 3") would help but I don't know how to machine that...

So, a 1" deep slit at 1/8" thickness would only work at 0.4 in/s of flow... Over 5 seconds?", that's only 2" of water movement :(

karimwassef
08/08/2015, 11:08 AM
Back to straws?

karimwassef
08/08/2015, 11:11 AM
So... If I accept 1in/s flow, and accept an imperfect flow (not fully developed laminar flow), then the slits are marginal at 1.25" depth.

karimwassef
08/08/2015, 11:22 AM
Redid the math for standard little coffee straws 5.25" long x 1/8" diameter. It works at double the flow even.

Speed v = 8in/s
Straw diameter d = 1/8"

Re = 694 v * d = 694 (ok)
Le = 41.6 v * d2 = 5in

So the 1/8" coffee straws at 5.25" would work at 8in/s of flow.
Keeping them in place becomes the problem. Mesh or netting before and after, maybe.

Mesh isn't rigid enough so I think I'd need to add eggcrate before and after..

Eggcrate
Mesh
Straws
Mesh
Eggcrate

ericarenee
08/08/2015, 11:28 AM
This

I still think to get the steady back and forth motion without over complex mechanics and less surface wake this is the solution..

As it will push and pull the water gently back and forth depending on the speed of the motor..no water pumps The mechanical assembly on the motor to rods a gear assembly on the motor with a rod offset on a flywheel.... the water motion can be adjusted with a controller if you use a DC Motor...

Instead of the rods connecting at the ends of the tank they could be above and would need not need the extra room on each end of the tank....

karimwassef
08/08/2015, 01:00 PM
I don't think the rods can go up since the top is sealed, right?

I think whether the drive is pump, motor-rid driven, pneumatic, actuated... The flow needs to be laminarized to avoid the energy going into a wave.

The in-tank piston only has linear action, so maybe it's the most efficient. The two sides don't actually have to be connected externally. The Pistons just need to be synchronized.

It does take up a lot of room though.

Length of the piston actuator (shaft/motor)+length of the piston chamber+linearizing box.
To move a 12" block, of water, it'll take 12+12+6 = 2.5' on each side. This probably works best with a pneumatic cylinder to move as hard and fast. To move more than a 12" block, the design needs to grow.

The pump approach is more wasteful, but much smaller I think. The space inside the tank is 6" + 2" for the plumbing ~ 8" on either side. But it needs a lot of external pipes and a massive pump like a Reeflo commercial 3HP Baldor. It also needs two three way valves and an actuator circuit. It is independent of the waterblock size though. So whether it's a 12" or 24" block of water, the pump can do either without more room. It's just a question of how long to keep the flow in that direction.

So - piston is probably most efficient and simplest, but the physical implementation requires more skill than I possess (giant hydraulic piston box) and is less flexible in making changes later.

The pump is not efficient, and requires more plumbing and circuit complexity (pipes, valves, actuators), but I know how to do that stuff. It should be more flexible to tune.

Both will need control circuitry, but I can do that part.

karimwassef
08/08/2015, 01:10 PM
I think it's s combination of the best way to do it and what I can actually DIY :)

ericarenee
08/08/2015, 01:16 PM
I think it's s combination of the best way to do it and what I can actually DIY :)

Got-Cha........ But i thought you could do anything....

karimwassef
08/08/2015, 01:28 PM
Thanks :)

I think the size is what's intimidating about these pistons. It takes a lot of power to move that much volume of water. Pumps do it internally, but a DIY massive piston and powerful actuators ... Probably needs a more skilled and experienced DIYer.

Probably can mock it up, and that's a good way to learn.

karimwassef
08/08/2015, 02:31 PM
Here's the pump/actuator setup for a simple max flow pump.

<a href="http://s1062.photobucket.com/user/karimwassef/media/1_zpsvh2md6se.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/1_zpsvh2md6se.jpg" border="0" alt=" photo 1_zpsvh2md6se.jpg"/></a>

Looks more complicated than it really is. The pump is always on and pumping in the same direction, the actuators turn together to convert the flow direction.

Can anyone see a way to make this plumbing simpler?

karimwassef
08/08/2015, 03:12 PM
stuck on the pump selection. Even the 3HP Reeflo Commercial Baldor pump can only do 12500gph. For a 24"x 24" cross section, that's about 1.4in/s. I'll need to downsize the boxes to 15"x 15". That may be ok since this is a retrofit for now and I can get that to fit into my existing tank.

That generates about 4in/s of motion using 2.5" of straw length. with 0.5" of eggcrate/mesh and 2" of plumbing, I think the box can be 15" x 15" x 5".

The pump has 88ft of head. I haven't calculated the back pressure of the box, but I don't expect it'll be that high (famous last words).

JamesHolt
08/08/2015, 06:01 PM
2 of these
http://www.calpumpshop.com/Cal-Pump-Model-T10000/Cal-Pump-Torpedo-Pump-10000-GPH-p-97.html
with the piping going from side to side..
Put them on a VFD to get better control..
You would just need to figure out the guide box to point the flow correctly

karimwassef
08/08/2015, 06:18 PM
Wow. Is it reef safe?
I've never used variable frequency drive. Do they have any off the shelf that would work or is it a DIY?

JamesHolt
08/08/2015, 06:48 PM
Dont know about it being "reef safe", they are made for Koi ponds, so I wouldnt think there are any harmful metals in it..
It looks to be made from a plastic/poly material..
You buy the VFD for the HP of the motor (and Phaseing)
They are simple to setup,, some even have inputs that will trigger preset speeds..
The VFD also controls the on/off of the motor via an input (normally a dry contact)

As for the slots in the guide box portion,, quit trying to mill them out,, just cut strips and stack them up..
Will be easier to mock up that way... :)

salty joe
08/08/2015, 07:32 PM
Something I've daydreamed about is using a motor to drive an arm that rocked back and forth from the center. Each end of the arm would have an attached displacement vessel. The vessels would rock up and down in the 1' tank ends. I realize this is very similar to what Jake2045 had in mind, but if the 1' ends were made taller than the tank and the wall separating the 1' sections had well placed, say 6" holes, couldn't that create the bulk water movement you're looking for without a wave?

karimwassef
08/08/2015, 08:15 PM
I'll think through the piston concepts again.

These 1KW or 3HP pumps are massive power hogs.

salty joe
08/08/2015, 08:31 PM
In my mind's eye, it was rigged up behind the tank. The 1' sections would be next to each other so the arm is only 2-3' long. 12" drain pipe would connect to the tank. I also had the vessels wrapped in mesh with 660nm LEDs shining on them for an algae filter. In my dreams, that is...
You build amazing stuff for your tank. Can't wait to see how this shakes out!

herring_fish
08/08/2015, 09:01 PM
I am a crazy designer by trade and I have given this issue a great bit of thought over the years. The solutions that I have come up with or have found are not easy. Unfortunately, most of them are quite ugly as well.

Most of the surge devices don’t remove water as fast as it is dumped in so in many cases you need an unused area above the standard water line to allow for the water to rise. That’s good for commercial aquariums and people that have a lot of money time and space but it won’t fit in my living room. More power to those that have more room to play with. I do have a 2 gallon dump bucket ATS above the tank but the splash is anemic. We are talking about large volume flow here.

I hope to peel off only part of the problem and try to address that. I want to use a single large pump to do the work along with a water flow switch.

I want to keep zooplankton alive in an NPS tank so I came up with a couple of non-traumatic pump designs but that is not very important for most reefers and I won’t explore them here.

Looking around the net, I saw that one engineer made this flow switch. This is a small version of what I wanted to build. Actually there are other switch designs that may work a lot better but this was the first one that I saw, many years ago. This is here just to explain the concept even though it was briefly mentioned earlier in the thread. With new 3-D printing many other designs are becoming feasible.


This project would require scaled up sizes and volumes in the design.

http://asaherring.com/reef/hardware/PumpSwitchDevice.jpg

I wanted to double the flow ports so that the pump could have pushed and pulled at the same time. The core would have looked something like this. I added this graphic that I modeled back then only to give you an idea of what I had in mind many years ago.

http://asaherring.com/reef/hardware/PumpSwitchCore.JPG

This graphic shows how water is pushed and pulled at the same time.

http://asaherring.com/reef/hardware/PumpSwitch.JPG

In this graphic, I show three pumps of different sizes (Bottom Left) that could be used together but I would just use one. The water flows through the single pump (Blue) and splits to go (Up) through the left side of the switch. Depending on where you are in the cycle, the water goes through the open side (O) and is held back on the other side (-). The open side goes to one side of the tank and the close to the other. The red side opens to pull at the same time so as to get better push/pull flow. Then everything smoothly slows, goes neutral and then reverses.


On the reef, I see (mostly on television) that there are lots of different cycle times on different reefs and/or different parts of the same reef and/or on different days. Given this freedom, I plan to have a longer cycle time of perhaps somewhere between 15 to 30 seconds total including dead time.

As stated earlier in the thread, there is a time when the switch is in transition and energy is wasted but on the other hand, the switching changes gradually, gracefully and naturally … at least in my imagination! You would have to weigh out whether ramping the pump up and down would save money over keeping the speed of the pump constant.

As for true laminar flow, I have looked at clear Plexiglas boxes at either end that run from front to back and from top to bottom but only 2 inches wide with different openings, including straws and a million other ideas …well maybe 50. I have looked at larger diameter clear tubing with outboard cowling, a little like the front of airliner fan jets. I have even looked into the patents for super soakers and Dyson bladeless fans. I designed and had built a similar structure before his but with a different purpose. There are lots of ideas but again, most are ugly.

I will tag along because I am more of a designer and a dreamer than a doer. At work, others actually produce my designs. At home I get very little done so I will be glad to see what you guys and gals can come up with and actually build.

JamesHolt
08/08/2015, 09:21 PM
I'll think through the piston concepts again.

These 1KW or 3HP pumps are massive power hogs.

Any way you do it will be costly to run, at least on the scale you want..
Something has to push the piston or pump the water,, pneumatic/hydraulic or mechanical. You are wanting to move alot of water...

The ideas so far would be perfect for smaller setups, or even a Nem only tank (no exposed powerheads).. Even raising the surge tank up to build speed will be costly since you have to get the water back up there...

I just dont see it working on the scale you want without it being costly to run..

On another note ,, Salty Joe that idea with the arm would make a killer steampunk theme tank,,if you are into that

karimwassef
08/09/2015, 08:29 AM
Welcome herring! I made my first alternating flow DIY back in the early 2000s and even reused the motor for my current design. I also used the parts to make my current surge actuator.

Roll the historical film - imagine shimmering memory clip here -

<a href="http://s1062.photobucket.com/user/karimwassef/media/F302B9BE-E9FB-41F9-B074-CD784BCBC8C9-2040-000001D0069ED3E1_zps2018a29e.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/F302B9BE-E9FB-41F9-B074-CD784BCBC8C9-2040-000001D0069ED3E1_zps2018a29e.jpg" border="0" alt=" photo F302B9BE-E9FB-41F9-B074-CD784BCBC8C9-2040-000001D0069ED3E1_zps2018a29e.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/F24AD132-E1BC-421D-B26F-2B64BADBC968-2040-000001D00E604B08_zpsac01bf22.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/F24AD132-E1BC-421D-B26F-2B64BADBC968-2040-000001D00E604B08_zpsac01bf22.jpg" border="0" alt=" photo F24AD132-E1BC-421D-B26F-2B64BADBC968-2040-000001D00E604B08_zpsac01bf22.jpg"/></a>

Here's my current alternator in design, test and use

<a href="http://s1062.photobucket.com/user/karimwassef/media/34EC2803-6AC4-4727-8D32-C31A78D6544A-368-0000004F1AE5E5DE_zps17466ec4.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/34EC2803-6AC4-4727-8D32-C31A78D6544A-368-0000004F1AE5E5DE_zps17466ec4.jpg" border="0" alt=" photo 34EC2803-6AC4-4727-8D32-C31A78D6544A-368-0000004F1AE5E5DE_zps17466ec4.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/CA7101FF-841C-4938-B2B6-D4665B590DA0-368-0000004F17ADB133_zps699ab4c3.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/CA7101FF-841C-4938-B2B6-D4665B590DA0-368-0000004F17ADB133_zps699ab4c3.jpg" border="0" alt=" photo CA7101FF-841C-4938-B2B6-D4665B590DA0-368-0000004F17ADB133_zps699ab4c3.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/E1F69AE7-6200-4A76-9F87-21F75DEC5A1B-177-00000019DE7171B7_zps28563a95.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/E1F69AE7-6200-4A76-9F87-21F75DEC5A1B-177-00000019DE7171B7_zps28563a95.jpg" border="0" alt=" photo E1F69AE7-6200-4A76-9F87-21F75DEC5A1B-177-00000019DE7171B7_zps28563a95.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/BC7D0B65-E2C8-45A8-B346-7EF45C82BF73-177-00000019DCAA1473_zps6b82cec1.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/BC7D0B65-E2C8-45A8-B346-7EF45C82BF73-177-00000019DCAA1473_zps6b82cec1.jpg" border="0" alt=" photo BC7D0B65-E2C8-45A8-B346-7EF45C82BF73-177-00000019DCAA1473_zps6b82cec1.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/4B6FC3D7-9FB6-414F-995D-4927DDAFD7D4-177-0000001A3CA655E0_zps7d031838.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/4B6FC3D7-9FB6-414F-995D-4927DDAFD7D4-177-0000001A3CA655E0_zps7d031838.jpg" border="0" alt=" photo 4B6FC3D7-9FB6-414F-995D-4927DDAFD7D4-177-0000001A3CA655E0_zps7d031838.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/79A78C72-47F7-4A35-A6DB-96AD8D643758-367-0000003AC16711F5_zpsa4d905e3.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/79A78C72-47F7-4A35-A6DB-96AD8D643758-367-0000003AC16711F5_zpsa4d905e3.jpg" border="0" alt=" photo 79A78C72-47F7-4A35-A6DB-96AD8D643758-367-0000003AC16711F5_zpsa4d905e3.jpg"/></a>

http://s1062.photobucket.com/user/karimwassef/media/106BF396-F986-4E27-B986-66CEBB1C0305-827-0000013EFC853B4A_zpsc78786c6.mp4.html

<a href="http://s1062.photobucket.com/user/karimwassef/media/4498AC40-8CE0-4047-9836-D44D27181C66_zpsfmr5dbco.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/4498AC40-8CE0-4047-9836-D44D27181C66_zpsfmr5dbco.jpg" border="0" alt=" photo 4498AC40-8CE0-4047-9836-D44D27181C66_zpsfmr5dbco.jpg"/></a>

And the usage

<a href="http://s1062.photobucket.com/user/karimwassef/media/D1A064B7-C3FC-46D5-92D1-10706AF6286F_zpsnhmf81m8.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/D1A064B7-C3FC-46D5-92D1-10706AF6286F_zpsnhmf81m8.jpg" border="0" alt=" photo D1A064B7-C3FC-46D5-92D1-10706AF6286F_zpsnhmf81m8.jpg"/></a>

karimwassef
08/09/2015, 08:36 AM
The flow alternator on my tank now gradually changes the direction of my return pump outlets. It's not the same as the laminar motion.

The difference is that the change in direction is sinusoidal. The laminar flow's timing isn't. The state is 5 sec one way 100%, 1 sec transition, 5 seconds the other way 100%, 1 sec transition...

That's why I was looking at three way valves for the flow motion here. That and I'm worried about a high pressure DIY at 20k gph. :D

karimwassef
08/09/2015, 08:47 AM
James, I agree. The power needed to move that much water that fast is high. The concern is the conversion of that power efficiently into linear motion.

I'll do some math on the output vs input power

ericarenee
08/09/2015, 09:02 AM
oops i found my answer to your drawing...

I think this will work if the pump is fast enough....

ericarenee
08/09/2015, 09:18 AM
Here's the pump/actuator setup for a simple max flow pump.

<a href="http://s1062.photobucket.com/user/karimwassef/media/1_zpsvh2md6se.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/1_zpsvh2md6se.jpg" border="0" alt=" photo 1_zpsvh2md6se.jpg"/></a>

Looks more complicated than it really is. The pump is always on and pumping in the same direction, the actuators turn together to convert the flow direction.

Can anyone see a way to make this plumbing simpler?


I Do not think the pump intake can keep up with the output.. Especially in the Right side (Last Drawing)
I have this issue with my Reeflo pump right now.. because of space there are elbows on the intake 1 1/2 two of them . 1 output 1 1/2 . i have to throttle the output way back to keep enough water feed into the pump . Going to Re drill the tank with 2 1/2 inch input to the pump...

Now According to reeflo. I can leave it as it is.. but just move the pump to have 3 feet from the last elbow to the pump input...

I Think you will need two loops. One to pull water and one to push.... with two bulkheads in each end of the tank....... If the tank was Pressurized none of the above would apply it would just bottleneck the pump....

karimwassef
08/09/2015, 09:41 AM
The two boxes are pressurized. There's no overflow/return. Intake box and output box see all pressure.

I agree on the distance from output to first elbox. I need to leave enough straight run to avoid losing a lot of head and flow.

karimwassef
08/09/2015, 09:48 AM
So the power to move a 24" x 24" x 20" box of water (assuming 4in/s for 5sec) is under 200W. This is raw force x velocity and completely lossless.

The 3HP pump can only deliver 1/3 of that motion ~ 1.4in/s... That's not the right answer.
The 1kW torpedo does 1/4 of the required flow ~ 1.1in/s... That's more efficient, but no right either.

If I downsize the boxes to 12" x 12", this becomes easier, but becomes more like a powerhead. It doesn't shift the volume, it creates a flow pushing and another pulling. The rest of the tank's volume will interfere with the two flows and stop the "shifting" motion.

karimwassef
08/09/2015, 09:51 AM
This is hard because the flow is massive. 4in/s at 24x24 cross-section is 36000gph!

karimwassef
08/09/2015, 10:21 AM
Ok - reset - to be realistic, I think 1in/s is viable.

That reduces the needed output power to 12W. That's a fictional number since it's a simplistic view of moving the water block without anything around it. It ignores all frictional forces that we need to overcome, ...

karimwassef
08/09/2015, 10:33 AM
Here are the new numbers:
To move 24" x 24" at 1in/s for 5 seconds one way:

The volume moved is 12gal at 9000gph, weighing 104lbs

Using 1/8th inch diameter straws, the flow is laminar with a length of 0.7in (smaller box). So the laminarizing box only needs to be 3.5" thick including plumbing.

The Torpedo pump should work if its reef safe. At 1000W, it's 1% efficient. :(

I'll look at the actuated pistons' math next.

karimwassef
08/09/2015, 10:39 AM
Taking all the piston ideas, here's what I'm thinking.

The pistons pushing up and down take up the least room from a practical implementation. The problem is that they create an up/down wave.

But using them as a bellows instead means that the depth of the tank can be converted into a sideways push. So, the motion is downward in a sealed box. That moves water that is channeled to point to the right. That's passed through the laminarizing box.

Two boxes on either end, one pulling water in, the other pushing water out. Synchronized.

karimwassef
08/09/2015, 11:32 AM
How's this?

<a href="http://s1062.photobucket.com/user/karimwassef/media/1_zps5xfddudk.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/1_zps5xfddudk.jpg" border="0" alt=" photo 1_zps5xfddudk.jpg"/></a>

karimwassef
08/09/2015, 11:39 AM
greater detail

<a href="http://s1062.photobucket.com/user/karimwassef/media/1_zpsqwlmumaj.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/1_zpsqwlmumaj.jpg" border="0" alt=" photo 1_zpsqwlmumaj.jpg"/></a>

if the piston is thin, then the injection box is 24" x 24" x 5".

I'm not confident in a seal without a large piston, 6" deep, or even 12". If the piston is 12", then the injection stage needs to double to 10": 24" x 24" x 10"

The baffles may be another 3"?

The laminar section is ~ 3"?

So 24" x 24" x 16" .... still big, but closer I think.

herring_fish
08/09/2015, 04:26 PM
“Roll the historical film - imagine shimmering memory clip here –“
Yes I have followed your work for a long time. I remember most of those pics. I have planned to copy some of your work but can’t try your new endeavor. Baby steps first.
Unfortunately, I am dyslexic so I mostly look at the pictures and didn’t read all of the text. Remember, I’m a guy ….”I don’t need to look at the directions.” …or do I?


I don’t remember getting all of the feedback on how your stuff worked.
“The difference is that the change in direction is sinusoidal. The laminar flow's timing isn't.”

It depends on where you are and when. Where you were, the reef itself didn’t thin out the body of water. It was moving much like it was all in a box on casters, shifting back and forth. (ignore the surface wave in the box)
At other paces, the reef causes the water to up-well and push over the reef structure causing a longer, more sinusoidal flow …even though it can be laminar. What you are trying to do is ambitious and requires a lot of power as you have already calculated.

I am looking at something like the 12 by 12 idea that you talked about. …understanding the down sides.



Going back to the full blown idea…

When I am brain storming, as you know, I think outside the box. (way outside!) As I was taught, bad ideas can be improved or fixed ….or can spur better ideas. So when it comes to ideas, I believe in quantity not quality. That is why I will just utter whatever comes to my mine, no matter how stupid it sounds.

I guess everyone that is reading this thread has mentally explored an external, open topped box above the tank with a baffle going back and forth. This external box has been done before. Often pushing and then pulling something with the same force saves energy over two separate units pushing at a different work output as when it is pulling or just reacting to the work of the other unit.

If the baffle and the sides of a rectangular vessel was taller than the resting waterline, the waves would not wash over. You would not need seals, just a close fit, not touching the walls. Seals would assuredly wear out in no time. At least that is what I have read. On the other hand, water blow by wouldn’t be that great as long as the waves didn’t over flow the baffle or sides. The water that goes upward in a wave would, of course come back down and act as a capacitor so energy would not be lost.

The vessel would not have to be made of glass so you wouldn’t have to worry about accumulated stress fractures and sudden catastrophic failure of the display tank. A problem would go back to piping the water to the two ends of the tank with minimal friction, also addressed earlier.

The narrow boxes at either end is the only thing that I have been able to think of over the years. Not being a fluids guy, I wonder if you would need the internal baffles. If the pressure inside the box exceeds the resistants’ of the straw wall, won’t the out flow be pretty close to equal without the baffles?
Now the main moving drive baffle (say, going left and right) would extend down into the vestal at a right angle. There would be a long moment or torque length produced by the long baffle so there would be a lot of stress on the slide mechanism that the drive baffle would be attached to. A geared motor could move the baffle left and right like a piston, piston rod and crank shaft in a car, only in reverse.

Again, I am probably not explaining anything that we have not all thought of before but it might cause someone to come up with a better idea.

karimwassef
08/09/2015, 04:42 PM
Thanks herring. Can you draw out your baffle box? I need to visualize it better.

I agree that the injection box doesn't need to be a super tight fit. I also agree that the baffles may not be needed due to the back pressure of the laminarizing box.

I am concerned with the pressure in the injection box. It might be so large that acrylic may not be a viable material.

The left/right pistons with a motor/gear/bar... I hear what you're saying about not needing a seal, just high walls. This supports erica's approach too. I'd need to mock it up, but you both may be right. I'll look at it again.

karimwassef
08/09/2015, 04:56 PM
On a more fundamental level, I was reading back on this thread and I've got a couple of glaring errors in logic and calculations.

I've been looking at the box of water being moved as a 24x24x20". This is wrong. If it were true, then that little subset of tank volume would represent a wave that moves through the tank. It doesn't represent the bulk of the tank moving to the right or left.

From a calculation point of view, I'm actually trying to move the 6' of water between the ends to move at 1in/s. So the power needed is much larger.

For a logical point of view, pushing against the bulk of the tank water at one end and pulling at the other end will not make the middle bulk of tank move left to right! It will create two opposing waves that will move depending on the properties of the medium (water). Each wave will propagate from its initiation point to the other. Left to Right + Right to Left.

If they happen to add up perfectly, I could have a standing wave. That I don't want. If they don't, I'll just have two laminar waves pushing through the tank in opposite directions. If they cancel perfectly, I think this could look like the bulk of the tanks is moving, but it will only happen after several cycles.

So, there is another level of design missing here. The timing and speed of the action (pump or piston) needs to be engineered.

I don't think there is a mechanism to move the middle bulk of water by pushing on the sides... :( the density and viscosity of water won't allow it unless the tank is very short. That's my conclusion so far.

karimwassef
08/09/2015, 05:26 PM
For those on this journey with me, here is my new favorite website.

http://www.insula.com.au/physics/1279/L14.html

It explains the longitudinal waves I was describing above as if it was written as a response to what I wrote! It's excellent.

herring_fish
08/09/2015, 05:32 PM
I haven't looked at the web sight yet but here goes anyway. Most of that is about waves. You don't want wave action.

I read a lot of my stuff on wave action and water movement in Dr. Adey's Dynamic Aquaria

I will get on the graphic.

As for the volume of water that needs to be moved, yes you have to move it all at the same time, including what is not seen. That is a lot of force! Industrial!

If you have a longer cycle time, you don’t have to worry (as much) about the wave action. Moving water that fast would cause things that are slightly akin to cavitation. Again, you would need to also have extra room above the display tank for wave overflow.

karimwassef
08/09/2015, 05:34 PM
Here is a pressure (longitudonal) wave created by a forcing wall on the left. In this case, it's bouncing off the right wall and interacting with the original wave.

http://www.insula.com.au/physics/1111images/lwave.gif

It's different than surface (transverse) wave that we're used to

http://www.insula.com.au/physics/1111images/twave.gif

Here's what happens with both

http://www.insula.com.au/physics/1111images/water.gif

All credit to the website I listed and Dr. Russell reference in it.

karimwassef
08/09/2015, 05:38 PM
Here is the animal from Dr Russell's website

http://www.acs.psu.edu/drussell/Demos/StandingWaves/StandingWaves.html

showing a standing longitudonal wave

http://www.acs.psu.edu/drussell/Demos/StandingWaves/standing.gif

I think this is as close as I can get to creating a bulk motion flow in a closed reef tank? It basically sets up multiple zones of high flow or no flow depending on the length of the tank and the wavelength.

So instead of one bulk motion, it forms multiple motion blocks. That might actually be better. It would allow placement of corals that prefer high flow and others that prefer low flow in the same display.

herring_fish
08/09/2015, 06:12 PM
http://asaherring.com/reef/hardware/BafflePump.jpg

This is not to scale and the rotation is not at the right point but I hope that this helps.

The (Blue) baffle moves left and right. It is attached to a carriage on a slide rail. There is a BIG rotating wheel that has to be the size of the displacement. There are ways to get around that but you get the idea I hope. As the wheel turns, it moves the carriage.

The baffle would create wave action that might be violent. The fact that the baffle is so long means that as you push it in the water, it will want to bend ...and the wheels on the track will want to bind because of the up and down pressure as the baffle wants to rotate instead of just push in a straight line.

Something like this has been done in big aquariums but at home, it would be a problem. Actually, it was a problem at full scale as well.

herring_fish
08/09/2015, 06:36 PM
Have you looked at making a homemade Gyre pump? It could be external, just above the tank. With that, you could have a water flowing away over the top and back along the bottom or out along the glass and back along the rock. A big paddle wheel could make for a comparatively laminar flow with less of a chaotic look of wave action. You could tune different parts of the tank for high flow and low flow.

karimwassef
08/09/2015, 06:47 PM
Is the giant baffle/paddle visible in the tank?

karimwassef
08/09/2015, 06:49 PM
Re the animation above:

Animation courtesy of Dr. Dan Russell, Grad. Prog. Acoustics, Penn State.

:D

herring_fish
08/09/2015, 07:30 PM
No This would be above the tank. I didn't draw in the plumbing going from either end to the display but they would just turn straight down to the dispersion box. The laminarizing box. Boy, I like saying that.

ericarenee
08/09/2015, 07:34 PM
OK..

I have been out all day doing other Life necessary things .. GRRR THAT SUCKS..

I see lots of thinking has been going on. Reading the above comments. I agree that even with the Large pistons pulling and pushing in sync the right would push water up right before mid way. and the left would pull water down causing a middle either untouched barely touched or Quite violent....

The only Solution i see in this And i think it also applies to the pump design as well the tank Body of water itself will need to be sealed..That would bring about another issue with moving water thru the sump for mechanical and gas exchange as this can not happen at the tank surface..

But at the same time. When you push say 24x24 sq x 1 inch.. Forward while pulling the same 6 feet away... it should pull the wave as a ripple .. (maybe not cause as much tension in the middle as my mind tells me.

I think a very primitive box needs to be built to scale and test some of the ideas if nothing but done by had without mechanical help... a wooden box would work......

Herring in your Diagram where is that baffle in relation to the reef ...
Having it over head like that would be good. But it would need to be two tracks far apart to allow proper light placement...or build out of very ridged material and just on say front or back to not impede on lighting.....

I could be looking at it wrong as well......

herring_fish
08/09/2015, 08:42 PM
This is a separate piece of equipment. It would be well above the tank or behind it. Again, I don’t think it is a good solution, just something that will make you say Hmmmmm and then maybe move on to something that would work better.

I still think that if the cycle time isn’t longer, the energy that is required will be very high and the problems will be great.

So once again, we are trying to figure out how to only move a the cross section of the tank 1 inch per second for four seconds and then reverse that. Right? or No?

Gorgok
08/09/2015, 09:36 PM
The only Solution i see in this And i think it also applies to the pump design as well the tank Body of water itself will need to be sealed.

This may actually be the key to making this idea possible on full length without sacrificing 2/3 of the tank to do it...

If you treat the display portion as a square tube, sealed on all walls, you will eventually get laminar flow through the bulk of it (minus the rockwork). Not sure how massive the pump would need to be, or the flow, but it could be done. Then after some time running in one direction you let it settle and reverse it. Do that a few times a day for tides going in and out.

I do wonder how large it would have to be though, would the flow have to be so high as to make having anything in the tank impossible? And what sort of plumbing would it take, 6"? 10", or the same size as the tank, as in a racetrack setup.

Though a racetrack tank would be lovely for this... Could achieve tide like flow with powerheads and time i'm sure.

karimwassef
08/10/2015, 07:32 AM
Gorgok, erica, I think I agree.

There are three big targets here: laminar, longitudinal, alternating.

Laminar I think we have a solution to pump in a laminar stream with the return along the same path. If left in one direction long enough with a high enough flow rate, the whole tank will eventually move in that direction (minus rock interference).

Longitudinal. This is the one I don't think works (or works yet). The incompressibility of water (especially in an open tank) means that the injected flow will push against the bulk and that water will not immediately be able to move in the same direction. It'll want to get out of the way and that will turn the longitudinal push into a transverse wave up and down. Well - two waves, one at each end. Eventually, with enough time, this should settle into a continuous flow, but not in 5 seconds.

A sealed top could force this to happen faster - acting like a pipe.
Another wild idea is to use acoustic waves. Sound is a longitudinal wave in water and an underwater acoustic source may be able to create motion that locally feels right and with phasing, could move that motion... Impact on fish and coral?? Unknown.

Alternating. After running some math, I think this is the real killer. For that much water to form laminar, longitudinal flow in 5 seconds, then switch and turn the other way for 5 seconds. All of this at 4in/s of flow... The math just doesn't work. At least not in a little rectangular tank with 10k pumps. The flow would have to be enormous to get the flow to line up that quickly throughout the length of the tank. Then to switch that fast, the transverse wave would rise feet out of the water.

Not seeing a path right now.

karimwassef
08/10/2015, 12:50 PM
To be clear, I don't want to set up surface waves or standing waves by pushing flow and have it bounce back from the opposite wall. I want the entire volume to shift to the left and then to the right. No waves. http://loanfinanceus.com/yellow/images/34.gifhttp://loanfinanceus.com/yellow/images/37.gif

So... I'm not sure who this is but you've posted twice under new names, so I'll assume you enjoy your anonymous poking at this thread. :D

That's fine. To be more specific - "no surface or transverse waves"

I would like whoever it is to come out and provide your perspective in a constructive and collaborative way. I won't go looking for every mistake you've made and posted to shame you, in exclusion of all the good results I'm sure you've achieved.

:wavehand:

herring_fish
08/10/2015, 12:54 PM
Don't go looking up MY stuff. :rollface: I would get laught off the site.

karimwassef
08/10/2015, 12:59 PM
LOL. Failure is just the path to greater knowledge.

ericarenee
08/10/2015, 03:35 PM
LOL. Failure is just the path to greater knowledge.

So Very True... If you never Fail you will never succeed


For what its worth . Here is some of what i do For a Living.. I Know all to well about Trial and Error to Find success

http://bonnieanderica.myds.me/photo/#!Albums/album_457269636120576f726b20416c62756d73

JamesHolt
08/10/2015, 04:54 PM
The 5 seconds is gonna be the kicker..
I have next week off ,,may try a few things at the house..

karimwassef
08/10/2015, 05:10 PM
Love the vlamingi and the build in reef. Especially the side viewable built in. Nice carpentry!

;)

karimwassef
08/10/2015, 05:12 PM
I find myself thinking more about that circular tank... Well, annular, like a donut or a raceway. Removing one sector could allow for some laminar flow options.

ericarenee
08/10/2015, 05:23 PM
Love the vlamingi and the build in reef. Especially the side viewable built in. Nice carpentry!

;)

Thanks she is a Pet Fish if there ever was one..if you look close on top her head you can see the scars from lateral line .. she was nearly dead when we got her. Poor fish . She now likes me to pat her and must be hand fed several times thou the day or she will Splash water out of the pond to get my Attention.
Bonnie has most of our life on there i think...That site is running on a server in the other room....

Thanks .. I can Build nearly anything with a steel stud and a screw gun.

I find myself thinking more about that circular tank... Well, annular, like a donut or a raceway. Removing one sector could allow for some laminar flow options.

This would be very kewl.. But I might get thrown out of the house for building that in the Living room.... Maybe out in the Work in progress room .. Hummmmmmmm ...

karimwassef
08/10/2015, 05:31 PM
Maybe the problem is scale. I can see this working on a 10gal tank with a big pump. I think that's the starting point for a proof of concept. Maybe a breeder 20.

With a short span, the problem become easier...

ericarenee
08/10/2015, 06:00 PM
Maybe the problem is scale. I can see this working on a 10gal tank with a big pump. I think that's the starting point for a proof of concept. Maybe a breeder 20.

With a short span, the problem become easier...


This could very well be a Place to start......

Gorgok
08/10/2015, 07:32 PM
Maybe the problem is scale. I can see this working on a 10gal tank with a big pump. I think that's the starting point for a proof of concept. Maybe a breeder 20.

With a short span, the problem become easier...

Theres no problem you cant solve with horsepower... Powerheads not enough? What about an outboard!


For the raceway tank stuff i was wondering how feasible it would be to just have a double rounded tank with a divider in the middle. No hollow, the divider is just to keep the front and back straights separate. It wouldn't be as efficient in the laminar flow as a true raceway i suspect. But would you be able to see an acrylic wall in say the middle of a 4' tank? If you keep it clean that is, and the edges are either covered or out of the water.

ericarenee
08/10/2015, 07:53 PM
Theres no problem you cant solve with horsepower... Powerheads not enough? What about an outboard!


For the raceway tank stuff i was wondering how feasible it would be to just have a double rounded tank with a divider in the middle. No hollow, the divider is just to keep the front and back straights separate. It wouldn't be as efficient in the laminar flow as a true raceway i suspect. But would you be able to see an acrylic wall in say the middle of a 4' tank? If you keep it clean that is, and the edges are either covered or out of the water.

This is kinda like my Pond is.. The drains to the sump are elbows turned to counter clockwise.. The Return from the sump is aimed Counter clock wise...
Can Drop food or a algae in the tank and it will go around and Around Until Mrs Mingi catches it..... The Return is about 6 inches down as to not disturb the top of the water as its a LOOK DOWN View wave or top water distortion would make it not able to see the fish ...The rock work is in the Center of the tank where there is a huge cave for Mingi....

ericarenee
08/10/2015, 08:01 PM
HUMMM The Raceway....

what if

You took a tank say 30 inches deep like mine..
put a false back in it say at 24 inches... cut some acrylic to round the back corners for performance maybe even the front... Make the fake back go say from 6 inches off each side of the tank.. But from the fake back to the front .
Leaving you with a tank that 24 inches deep with 6 inch on each end . Use DC PUMPS INSIDE THE BACK Area of the tank to push and Pull water thru the baffles.

basically a U Shape insert into the tank... The pump input aimed from the left and the output aimed to the right . Behind the wall... This would actually be full water movement.... THE Water would build momentum. When it reaches it peak have a second pump turn on the other direction... High volume at 9 head height dc pumps are under 200.00 ... And Will move massive amounts of water..
Still use the same plate on the baffle in the front... on each end... ..

karimwassef
08/10/2015, 08:37 PM
I think the circular shape is important. The curve guides the flow.

If the proof of concept on a small tank works, it may be that this can be built into the rockwork to create zones of swaying laminar flow... Zones of directed and channeled flow.

herring_fish
08/11/2015, 09:47 AM
So once again, we are trying to figure out how to only move a cross section of the tank 1 inch per second for four seconds and then reverse that. Right? or No?


Ok here’s some more thinking out loud.

If you are looking at a false back raceway, you could use the moving baffle idea with perhaps 3 or more baffles. Let’s call them paddles. With three paddles attached to one carriage, you would get less cavitation. That’s a miss-use of the work but it kind of fits. Actually, you would want to pack as many as you could back there so each one would create less wave action between them. I don’t know it might be 3, 6, 12, whatever.

How you would actuate it is another issue but when you move water at one point in the tank like that, you move it everywhere …excepting splashing waves. If you move three or more paddles in the back of the tank, the front will move as well.

The up side would be that you wouldn’t move one paddle a long distance, you would move several only 4 inches. Think small. It is still a LOT of energy but it would be only a baby elephant to move.

herring_fish
08/11/2015, 09:56 AM
..Or you could use a paddle wheel with half of the wheel sticking up out of the tank.

Ericarenee I looked at you work. I wish that you lived in my city. If you did, I would try to hire you to build some of my nuttier marine ideas.

karimwassef
08/11/2015, 10:05 AM
So the problem is distance.
Let's say you had a long rectangular tank (like a channel) and you could move an entire side wall (the small wall at one end) at slow speed down the channel. The end of the tank won't know anything has happened for 10 seconds. What would happen is that the moving side wall creates a surface wave (transverse) as the bulk water gets out of the way. The energy slowly moves down the channel as more transverse (surface) and less longitudinal (bulk) because it's easier to push air than water. Also, the bottom of the tank is stationary and creates resistance to the water touching it. By the time you get to the far end, it's just an ordinary surface wave. And it gets there many seconds later.

It's just a wave. Governed by distance, time, and material properties.

Pushing faster makes it get there faster but it's still a wave. No channeling of bulk water.

karimwassef
08/11/2015, 11:34 AM
Ok. Imagine a circular tank. Not a donut or racetrack, a big cylinder.

In the middle, imagine a large paddle wheel that goes all the way from above the surface to the floor of the tank.

Turn the paddle wheel clockwise, the water at the paddle wheel starts to flow around in the same direction. After a few seconds, the whole tank is flowing in the circular pattern. His assumes the paddle wheel is big enough relative to the tank diameter.

Now, the wheel slows down, and reverses. Repeat....

This will work - I think

How to disguise the paddle wheel? Protect fish? Overflow?

Some engineering problems to solve but I think I see hope!!

karimwassef
08/11/2015, 01:17 PM
Alternatively, you could leave the water in place and mount a rotating disk big enough to hold the entire display. Think giant microwave turntable.

Now the corals move and the water stays in place - back to my first example in the first post.

Probably not an enjoyable experience for the viewer or the non-sessile inhabitants, but the flow would be right! :)

That last bit is just fanciful.

I do like the idea of a paddle wheel centered cylindrical tank. Very few moving parts. Looks like a blower from above. Just need to keep the living things from getting wrapped around the axle.

Maybe an eggcrate cylindrical wall painted black with a black center and black paddle wheel?

The rockwork will need to be very open and airy.

Maybe several overflows in the forms of a rock mountain with a volcano top? Like volcanic islands that suck water from the top.

Now I just need a clear circular tub to experiment with. Maybe I'll get a giant plastic can of cheese balls and cut off the top.

ericarenee
08/11/2015, 03:52 PM
..Or you could use a paddle wheel with half of the wheel sticking up out of the tank.

Ericarenee I looked at you work. I wish that you lived in my city. If you did, I would try to hire you to build some of my nuttier marine ideas.

Thanks.. You could always move to Kentucky.. Louisville is a Awesome Place to Live.

The paddle wheel sounds interesting.

Ok. Imagine a circular tank. Not a donut or racetrack, a big cylinder.

In the middle, imagine a large paddle wheel that goes all the way from above the surface to the floor of the tank.

Turn the paddle wheel clockwise, the water at the paddle wheel starts to flow around in the same direction. After a few seconds, the whole tank is flowing in the circular pattern. His assumes the paddle wheel is big enough relative to the tank diameter.

Now, the wheel slows down, and reverses. Repeat....

This will work - I think

How to disguise the paddle wheel? Protect fish? Overflow?

Some engineering problems to solve but I think I see hope!!

Will have to think about this one... But yea would be simple to implement both motor and Controller design.. Not TO Mention Cost effective

For some reason i am stock on the need to pull and push the water at the same time..... But I We did cut the grass today. Lots of pushing and Pulling with that... GRRRRRRRRRR Blue grass SUCKS... Never plant blue grass....

Newtybar
08/11/2015, 04:23 PM
It could work if both walls are slanted...

ericarenee
08/11/2015, 04:59 PM
Ok. Imagine a circular tank. Not a donut or racetrack, a big cylinder.

In the middle, imagine a large paddle wheel that goes all the way from above the surface to the floor of the tank.

Turn the paddle wheel clockwise, the water at the paddle wheel starts to flow around in the same direction. After a few seconds, the whole tank is flowing in the circular pattern. His assumes the paddle wheel is big enough relative to the tank diameter.

Now, the wheel slows down, and reverses. Repeat....

This will work - I think

How to disguise the paddle wheel? Protect fish? Overflow?

Some engineering problems to solve but I think I see hope!!


This Could Work Quite well... But I just do not see how to get the volume of water to spin and Keep Fish away from the Paddles..
Unless the paddles themselves were part of the decor of the tank There speed would only need to be very slow if sized right.. Coral shape paddles ?????? Anything you did to protect them like screen or a shroud would also defeat the water movement ....

I do not like Cylinder tanks...


But i do have a Octagon tank in the basement.. its like 40 something gallons i think...

karimwassef
08/11/2015, 05:42 PM
It could work if both walls are slanted...

Why?

Imagine a black fence that allows water to move through it. The paddles would be less effective but it should still work.

karimwassef
08/11/2015, 05:45 PM
The reason I think circular is the answer is because it pulls and pushes at the same time.

Thick of a egg beater paddle in soup. After a couple of cranks, everything is going around.

Or a spoon in coffee.

The cylindrical shape takes energy in many directions and coverts it to rotational flow. It's a natural channel.

ericarenee
08/11/2015, 06:53 PM
The reason I think circular is the answer is because it pulls and pushes at the same time.

Thick of a egg beater paddle in soup. After a couple of cranks, everything is going around.

Or a spoon in coffee.

The cylindrical shape takes energy in many directions and coverts it to rotational flow. It's a natural channel.

I agree.... and with a much less powerful motor.

Will fish go mad swimming in Circles in a Round TANK...?:rollface::rollface::rollface:

Sorry have to ask....:fun4::spin1:

Gorgok
08/11/2015, 07:26 PM
I can get the entire body of water moving in a 18'x 4-1/2' round pool moving with just a pair returns pointed in the same direction on the wall... you don't need paddles. I don't even think the returns are much in terms of flow. It just takes time. Bigger returns in a much smaller tank would do it much quicker, though with a whirlpool like that you end up with a higher water level on the outside than in the center...

Circular tanks have their own issues though, which is why i think a racetrack with a thin center wall would be a decent enough compromise. Again i would use returns or powerheads for the motion, and just let it build up, instead of trying to force it to happen in ~5 seconds.

karimwassef
08/11/2015, 09:07 PM
Thanks erica and Gorgok.

I think that powerheads do an adequate job, but they don't achieve the bulk laminar flow I experienced.

I think time does matter. My tank has amazing wave action and flow, but the impact of this bulk alternating flow is different. It creates little stress but continuously moves and refreshes the polyps.

I like jacuzzis. I like wave pools. But the sensation in the reef is neither.

By the way, I'm not talking about a vortex. The flow around the inner wall will be faster, but not more than a powerhead's max speed. The fish won't get dizzy.
The reality is that their natural environment is like this.

The bulk flow doesn't need to be the only flow. It's also not always on either.

I'm wondering what shape paddle wheel would be most effective (fast) in creating a smooth laminar circular flow with the least energy.

Someone must have done this for another application already.

herring_fish
08/11/2015, 10:48 PM
ericarenee I visited Louisville but I did live in Lexington. '90 to about '94 That's where I got my first reef tank.


Ok back to the problems at hand.

Ok. Imagine a circular tank. Not a donut or racetrack, a big cylinder. ...
...Now, the wheel slows down, and reverses. Repeat....
This is a comment to laugh at but it might be easier to oscillate the coral bed, back and forth against standing water than moving the water.

Plenty of people have done laminar flow tanks before, long and short raceway tanks, raceway tanks that go up and over instead of going to the back, round tanks, yep.

The problem is laminar --- alternating flow. Then you throw in the 0 to 60 in 16 seconds. Well 1 inch per second but without being su, su, sinusoidal.

So, powerwise, you are looking for something more like square a wave than a sine wave right?

I don't remember the size of your tank but are we talking about 2000 pounds of water stopping on a dime?

Just keep'en it real here for a moment. Can we compromise on any of these points?

karimwassef
08/11/2015, 11:47 PM
I think sinusoidal is ok. While it didn't feel sinusoidal, working through the math when I was looking at the wave forms, I can see that the frequency and speed of the flow will be close to my experience even with a sinusoidal excitation.

It's also the easiest way to avoid crashing waves.

A smooth transition to zero and reversal will only be possible with a sine.

This also works well with a large motor and a circular tank.

I haven't done the works on the equations yet. I think a mock up is pretty easy in this case, so I might do that first.

karimwassef
08/12/2015, 12:03 AM
New terms: coating and rimming flow

http://eprints.maths.ox.ac.uk/1564/1/finalOR61.pdf

Not quite the same thing, but may be relevant.

karimwassef
08/12/2015, 12:19 AM
Another term: circular couette flow

https://uwaterloo.ca/applied-mathematics/current-undergraduates/continuum-and-fluid-mechanics-students/amath-463-students/laminar-flow

karimwassef
08/12/2015, 11:17 AM
To be clear, I don't want to set up surface waves or standing waves by pushing flow and have it bounce back from the opposite wall. I want the entire volume to shift to the left and then to the right. No waves. http://loanfinanceus.com/yellow/images/34.gifhttp://loanfinanceus.com/yellow/images/37.gif

What is the point of anonymously copy-pasting the same sentence that you don't understand?

mhurley
08/12/2015, 01:12 PM
It's a spam bot...He's not asking you a question. You're not seeing the hidden link he keeps trying to post. I'll take care of them.

karimwassef
08/12/2015, 04:19 PM
Thank you

karimwassef
08/13/2015, 01:53 PM
http://web.stanford.edu/group/uq/pdfs/journals/aiche_ib_04.pdf

It's a start :)

ericarenee
08/13/2015, 04:14 PM
http://web.stanford.edu/group/uq/pdfs/journals/aiche_ib_04.pdf

It's a start :)

Nice i will read this later...

Right now i am planing out my New Fuge.. Its going to be a Bit over 6 foot long Made out of a 55 gallon drum split. Its that or start selling Plants . As my Current Fuge is way over grown.....

Going to turn the current fuge into a Frag tank.......

karimwassef
08/13/2015, 05:24 PM
Nice. I just use a 100g Rubbermaid.

Selling plants? Like macro?

So I'm working out the formulas for this tank and the wheel design.

I'm thinking of a 10ft diameter, 2ft high tank. The paddle wheel (or impeller) is 4ft tip to tip with a 1ft round center. Each of the blades is then 1.5ft.

It's driven by a DC motor above the tank.

The impeller's central shaft also doubles as the overflow...

The way this works is : the tank's overflow is an 11" cylinder that's 22" high in the middle of the tank. The impeller is a 12" pipe with the blades attached. The 12" pipe fits around the 11" overflow like a wheel on an axle.

The impeller's shaft has a 3" opening that runs between the blades right at the overflow level.

At the 4ft diameter, a black plastic grate is shaped like a cylinder. The top is covered to prevent light from getting in.

The coral area is th annulus remaining. It's 3' deep x 2' wide and goes around the length which is around 31ft. That's about 1000gal of usable tank. The impeller and overflowing occupy another 200gal in the middle.

I'll draw it up.

ericarenee
08/13/2015, 05:37 PM
Nice. I just use a 100g Rubbermaid.

Selling plants? Like macro?




I'll draw it up.


I have done the rubber maid tank .. The reason i like the barrel idea is the rounded bottom.. Lots of surface area with less water volume..sediment should setting in the middle at the bottom....


10 FOOT Radius tank.. wow Ambitious.... Cant wait to see .. I do think it will work

karimwassef
08/13/2015, 10:44 PM
Moved to 8ft.

Playing around with the variables. I like the final version here.

<iframe width="560" height="315" src="https://www.youtube.com/embed/p69tsrWjX00" frameborder="0" allowfullscreen></iframe>

herring_fish
08/13/2015, 10:48 PM
(Edit: I put this together tonight before reading several posts so I am behind before I get started. I posted this and then read back. I will just leave it as is. Some of it fits what you are talking about.)

I thought that I would add just a little more detail to what I was talking about earlier. These ideas could be applied to straight raceway tanks or cylindrical tanks. This could get you close to what I think that you want.

There is a wide variety of rails and carriages. These are linear.

http://images.channeladvisor.com/Sell/SSProfiles/82000055/Images/276/J35D0261.jpg

These are curved so you could use them on a circular tank.

http://img.directindustry.com/images_di/photo-m2/linear-guides-for-curved-tracks-7243-2639339.jpg

The action of this simple drive piston pushing a wheel converts straight motion into circular. We could turn that around and get a motor driven wheel to push a carriage either linearly or around an 1/8th circle. I think that this will save electric power because the motor can run at a steady state. I am not sure because that is another area that I know nothing about.

https://d2t1xqejof9utc.cloudfront.net/sketches/pics/1713/thumb.jpg?1334035363

Four paddles could be placed parallel to each other. Plexiglas sides would keep the paddle pointed straight down and not allow them to bend as they are dragged through the water. There would be sides but no top or bottom. The box of paddles would be just small enough to miss the walls by a very small margin.

http://asaherring.com/reef/hardware/FourPaddles.jpg

This box of paddles could be attached to the carriage to be moved back and forth by the rod and motorized wheel.

http://asaherring.com/reef/hardware/RaceWayTanks.jpg

If you have the divider in the center of the tank, the paddle would only need to move 4 inches. If the divider is at the 1/3rd mark, then I think that the paddles would move 8 inches.

In either case, that is not too far. I also think that the more paddles that you have the less unwanted wave action you will get at those paddles.

This would be true if you had a round tank with paddles that are arranged like spokes in the back part of the tank. In this case, the paddles would be visible but not brake a plain that divide the front and back halves of the tank. They would be strengthened with a Plexiglas top and bottom.

Below I have a drawing that is very rough so you still my not be able to follow what I have in mind. Hopefully, you can see that I tried to draw the carriage over the back half of the tank and the paddle box extending into that half. Above it all is the motor, wheel and drive rod that is attached to the carriage.
http://asaherring.com/reef/hardware/WaveTank.jpg

karimwassef
08/13/2015, 11:29 PM
Great ideas, herring. I especially like these.

http://asaherring.com/reef/hardware/RaceWayTanks.jpg

If you have the divider in the center of the tank, the paddle would only need to move 4 inches. If the divider is at the 1/3rd mark, then I think that the paddles would move 8 inches.

In either case, that is not too far. I also think that the more paddles that you have the less unwanted wave action you will get at those paddles.


Excellent and very clear descriptions and illustrations.

karimwassef
08/13/2015, 11:32 PM
Putting the paddles and the separator inside the tank actually simplifies the mechanism. It doesn't consume 1/3 of the tank left to right.

It does consume the thickness, but that's actually more practical IMO.

herring_fish
08/13/2015, 11:56 PM
I m on the east coast so I am off to bed but which aplication are you wanting to explore further?

Gorgok
08/14/2015, 01:46 AM
Won't those inside spaces/paddles basically be wasted energy as its just moving a (semi-sealed) tank around... Only the paddles that touch the rest of the raceway affect the flow there really.

If you just moved one paddle from the left to the right the whole way you would be moving much more water on the front of the raceway than with the short stroke of the multi setup.

Taking this track and paddle idea further though you could incorporate a rotator into the single paddle. So it acts like an oar when rowing. Perpendicular on the stroke, parallel on the return or when idle (so as not to kill the flow already established).

Still more complicated than necessary i think, especially if using a narrow/wide raceway tank like the second rectangle shown. Having the returns blow one way in the narrow bit for a time, then the other should create the same effect. And it keeps that space of the tank less hostile to life i would think.

karimwassef
08/14/2015, 06:27 AM
Gorgok- I think th difference between a paddle and a pump is loss and flow pattern. The pump would need to channel the flow through pipes, a pressurized chamber, and a circular output with a narrow round flow pattern. That's a lot of wasted energy and needs the pattern to be laminarized. Pumps are also single directional adding to the complexity in reversing the flow (valves, etc...). The exception would be the torpedo pump from a few pages back. It's a direct flow it's a 3" intake and outlet and can even be used as a powered (submersible). It's still one directional, but I can see running two in series in opposite direction with a shared chamber between them. It may take several (4 pointing left, 4 pointing right, a chamber between the left and right) to get there.

It can work but it's getting very expensive to duplicate the paddle with a pump.

Edit- the pumps do have one key benefit: flexibility. The paddles are limited in stroke length in the channel. This is a hard physical limit. Pumps can operate for minutes in the same direction (emulating an infinite channel). So the paddles work for the 4-15 seconds I am looking for, but we still haven't resolved the surface wave effect.

I think the multipaddle concept is based on the idea of using the wasted volume between the paddles to create momentum. I don't think the seals between the paddles and channel will be tight, so this reduces the stress per paddle and uses the volume between them to get the motion going one way with less energy once started. Needs some engineering.

karimwassef
08/14/2015, 06:33 AM
So, thinking more about this. The reason I went round was to avoid turning the push into surface waves. Not sure I proved that it works yet, especially when reversing direction.

The channeled paddles idea has the same question with one more complication: the ends need to be shaped like circles to channel the flow into the laminal rectangle block in the front.

That radius and shape needs to work at the speeds we want to create laminar flow.

karimwassef
08/14/2015, 07:21 AM
The outlets need to be channeled. This means that the top of the tank at the outlets needs to be sealed to avoid the surface wave effect.

herring_fish
08/14/2015, 07:51 AM
The outlets need to be channeled. This means that the top of the tank at the outlets needs to be sealed to avoid the surface wave effect.

What do you mean? I just can't quite paint a picture of what you are saying. Can you rewrithe it in a different way?

Also:
So are you still looking at both the round and the rectangle designs?

herring_fish
08/14/2015, 07:53 AM
In post 113, I talk about the problem of a single paddle and show the splashing. Since you are trying to accelerate all of the water in the display tank at the same time, using more paddles allows more places to get a grip on the mass with less wave action and splashing. Yes that is a waste in one respect but you have to move it all if you want laminar flow. That is what is happening in the scuba experience. It’s all moving one way and then the other.

This wave action needs to be minimized to keep the water as laminar and ripple free as possible, in the front of the divider. Of course that is just how it looks in my imagination and from what I have seen. Experimentation at that scale is the only way to know which of these several ideas will work best in this application.

I have also thought about making a box that is fully closed below the water line so that it displaces the water between the front and back paddle. This would get most of the same splashing of the one paddle system but there would be less total volume in the system for the paddle (box) to accelerate. Again, there would still need to have close gaps between the back wall of the display tank, bottom and center divider.

This would be true of the circular tank or the linear. Depending on the design, the total volume might be cut by 30 to 40 percent.

Rotating the paddle(s) is a technique that is used to allow the paddle to work in one direction only or one direction more than the other. From what I understand earlier, we want the water to go in one direction, stop and reverse so a straight paddle setup should address that goal.

Any kind of pump(s) that cannot propel the entire cross section of the tank at the required speed would cause non-laminar flow. If it can meet that requirement, you then need to use the straw box or something like it to reduce the chaos of the pump and piping.

Again, if I get around to it, I will try to achieve a less ambitious tube of comparatively laminar water flow going down the center of the tank cross section. Cowling and direction jetting can improve the flow of a large diameter pipe outlet by pulling in water that is near the outlet to amplify the total tube flow size but that is not what we are looking for here unless we can come up with a better set of ideas.

Finally, with a 4 second thrust in one direction, it would be a 9 or 10 second cycle. A 15 second thrust, which is your new outside limit, would be about 30 to 35 seconds. Am I reading you correctly? Of course 10 and 30 seconds is a big difference. It will be interesting to see which end of the range you will be able to hit, if at all.

Something talls me that you get what you want if you are willing to work for it. Good Luck

ericarenee
08/14/2015, 08:08 AM
The outlets need to be channeled. This means that the top of the tank at the outlets needs to be sealed to avoid the surface wave effect.

I still believe the top water surface will have to have some kind of wave control..Being Sealed or maybe even a flat slotted top just below the water surface to break the waves... but allow some water to move up.....To help the momentum....


This applies to any of the design ideas.. I would like to see a actually test.
I could be wrong....... Hummmmmmm Erica Wrong.... :uhoh3:

karimwassef
08/14/2015, 11:50 AM
I agree on a sealed top to channel the flow for some distance.
Circle or oblong rectangle? Not sure yet.
Multiple paddles vs one vs pump. Not sure yet.

10svs. 20sec... Yes. I think this changes with size. On a small volume, the inertia s different than on 1000gal. The time it takes to reverse without huge waves changes. That's the struggle.

herring_fish
08/14/2015, 12:30 PM
I also agree with the top plate wave limiter idea.

Make sure that it is stout, like ¼ inch plastic or something. A 5 or 10 gallon wave might be too big or too small but almost any wave going that fast could be a problem.

I have used a 2 gallon dump bucket that has pushed flimsy plastic up and out of the way. .. the wave that comes from a dump bucket is nothing compared to this potential issue.

In a mockup though, you might just get a little water on the floor and can adjust afterwards.

karimwassef
08/14/2015, 03:42 PM
For a mockup, it'll be small and thin acrylic is ok.

For a real setup, this is likely just as thick as the tank's walls.

karimwassef
08/14/2015, 07:39 PM
http://images.channeladvisor.com/Sell/SSProfiles/82000055/Images/276/J35D0261.jpg

Where did you find this? What's it called?

herring_fish
08/14/2015, 07:51 PM
Just Google these and look under Images:

linear guide rail and carriage
linear guide rail and carriage
rail and carriage
carriage and rail
linear rail
circular rail
curved rail
curved rail and carriage

karimwassef
08/14/2015, 08:17 PM
thanks. interesting options. This one shows some potential benefits in controlling motion around a corner

http://www.designworldonline.com/uploads/Imagegallery/curvilinear-guide-systems.jpg

karimwassef
08/14/2015, 08:21 PM
most are screw driven, so I don't know how fast these can be... or how much power they can deliver.

herring_fish
08/14/2015, 09:33 PM
Yes there are a ton of options. Somebody makes a solution for whatever you come up with. I can give you some more information once you get closer to making a few decisions that will narrow things down.

Unfortunately, I have to keep being the Grinch here. I have to keep reminding us about the scale of what you are wanting to do. This would be a lot of force that will be exerted against the water. That reversing action is a hard nut to crack but do-able. The expense may not be prohibitive at all ….but I think you will have to think about beefy construction.

I keep guessing. How many gallons do you plan to have in your tank? If it is 2000 pounds, imagine moving your car back and forth with an electric motor.

Personally, I would like to steer you into straight linear or circular driving but not both. If you go with circular, you probably don’t need rails and carriages. If you go with the raceway, I would just stick with linear only.

I really like the piston, rod and crank shaft style of getting reciprocal movement for either the linear or the circular system.

Hopefully, other people will have some input on what we are looking into or have an entirely different direction that will help us. Otherwise, a few phone calls or Skype group calls would shorten the design cycle.

Please help us. Just throw out your great or stupid ideas. Perhaps we can use it as is or fill in the week spots and fine tune it. There is strength in numbers! Come on please chime in.

Gorgok
08/14/2015, 10:11 PM
most are screw driven, so I don't know how fast these can be... or how much power they can deliver.

Power isn't a problem with a screw, or shouldn't be unless its made of garbage... I see paddles or the joints to the carriage breaking way before the actual drive. Speed could be an issue, but higher speeds will make taller waves anyway.

On the multi-paddle thing, lets just go by a perfect seal first... If you move the thing 5" in a 5" wide channel 5" tall you have displaced ~1/2 a gallon of water from the front of the setup and drawn in the same at the back. The interior space just moved... It could be made of foam or air or water, it doesn't affect the rest of the system other than adding (live) mass to the carriage. If you move a single paddle the same 5" you displace the same 1/2 gallon with the same wave on the outside paddles.

If you move that carriage instead something like 25" since now you only have the one paddle so room isn't an issue you instead displace ~2.5 gallons.

Now it won't have a perfect seal, so the exterior paddles will bleed some when it starts to move and the interior ones will catch some of it, and when it stops the exterior paddles will block most of the flow the interior ones make but not all. This might raise the efficiency of a multi paddle setup over a single one a few percent, but 'total displacement' seen by the tank is still based on the outside loop. Being 80% efficient at moving 2.5 gallons will beat 90% efficient at 1/2 a gallon.

All this thinking about stroke stuff got me thinking of engines, so now we can think about the bore too. With a narrow channel you need to move farther to cause the same displacement as a wide one. And the faster you try to accelerate the water the taller a wave it will create at the paddle. So at the same speed, a wider channel should create a smaller wave with more displacement.

How much displacement will you need to actually see an effect on the live side of the loop? Thats probably a percentage of the volume on that side... maybe 25% to start? If you can shift 25% of the volume it should be pretty noticeable i think, at least on a 4+' tank that would be a pretty big deal... Calculations for the minimum size to hit that should be pretty simple in any given tank. Stroke is limited to total length minus a little bit. Height is just he water level. Then the only variable you really have to play with is the width. On a 75 thats maybe 44" of stroke and 20" tall. With 4" of channel you displace 15 gallons with roughly 58 gallons of display or 25%. At 5" its 19 and 54, or about 35%. At 3" its 11 and 62, or 18%. Even at 2", 7.5 gallons for 66 its about 12%.

None of those sound too bad, but it is still short lived, always limited to stroke unlike with a pump (at least until you rotate/raise the paddle out at the end of a stroke).

karimwassef
08/14/2015, 11:49 PM
This is 8' x 3.5'

The display tank is 2'
The overflow is 0.5'
The channel is 1'

So the ratio is 1:2

If we can make a good seal, one paddle is fine. otherwise, more paddles should make up for the poor seals.

<a href="http://s1062.photobucket.com/user/karimwassef/media/1_zpsvshs5lvt.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/1_zpsvshs5lvt.jpg" border="0" alt=" photo 1_zpsvshs5lvt.jpg"/></a>

The display tank is too small ... 4.5' x 2' but it can be scaled. in length.

karimwassef
08/14/2015, 11:51 PM
Maybe rectangular channels would work too, but not as well.

karimwassef
08/15/2015, 07:09 AM
Scaled and completely covered except for display and overflow. I think this is a reasonable balanced size

<a href="http://s1062.photobucket.com/user/karimwassef/media/1_zpsyhu2toge.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/1_zpsyhu2toge.jpg" border="0" alt=" photo 1_zpsyhu2toge.jpg"/></a>

still a little wasteful to dedicate 2 x 150 gal = 300 gal to the curved sides and 2 x 22 gal = 44 gal on the linear ends... 344 gal to curve.

~910gal

360 gal display (40% of total)
135 gal to channel + 345 gal curve = 480 gal (52%) ... wow
70 gal overflow (8%)

karimwassef
08/15/2015, 08:26 AM
Does anyone have experience running free CFD simulation tools like OpenFoam or OpenFlow? I think that's the next step and it's been a decade since I did that.

ericarenee
08/15/2015, 11:59 AM
Does anyone have experience running free CFD simulation tools like OpenFoam or OpenFlow? I think that's the next step and it's been a decade since I did that.

Blind faith and Build .....

Hurry up now...

Its gotta work

herring_fish
08/15/2015, 01:40 PM
Gorgok You might be right. We will have to see what actually happens when the experiments are run.

As you paint a picture, whether it turns out to be all correct, partially right or even all wrong, nothing that comes up will be a surprise because of all of the input from you and the rest of us. Keep it coming.

We have already added a partial or total cover based on ericaree’s idea.

Karimwassef I am hoping that you will not need to use the baffles and eggcrate because I am guessing that the water will be comparatively laminar coming off of the paddle’s smooth pushing. Then (in effect) the pressure should drop as the water goes around the curve. That should smooth things out even more.

…but

Blind faith and Build .....

Hurry up now...

Its gotta work

karimwassef
08/15/2015, 01:51 PM
The injection channel is 1' and the tank is 3'. Without channeling, the water will not flow around linearly. It will start to curve, but most will travel along the path of least change against the tank front with a width of 1'. That will create waves and turbulence against the other 2ft of width, losing the laminar bulk motion.

This refers to the curved baffles.

karimwassef
08/15/2015, 01:53 PM
The eggcrate will be necessary to stop as many of the living creatures from getting into the mechanism. It's one thing for a 1" blenny to wiggle back there. It's another for a 10" naso to try to make the baffles his new hiding place.

This is especially true since the flow will not be continuous. There will be quiet periods where curiosity will make explorers venture into the darkness of the mechanism.

When we show this works, we still need to work out the logistics of maintenance and cleaning.

The straight baffles may not be necessary but that depends on many variables still in design.

This is why I want to simulate the flow. I want to start with the circular sides and then start pushing them in to become curved corner straight edges. As the corner curvature increases, the flow will become more disrupted locally and flow will drop.

The baseline should be the flow with the ideal circle. Flow from other designs can then be compared to it. That establishes the design trade off. I would like to have less than 1' on each end dedicated to the mechanism, but I wouldn't want to lose more that 20% of the flow.

herring_fish
08/15/2015, 01:53 PM
Yea you might be right.

karimwassef
08/15/2015, 02:09 PM
I agree on erica's idea before. I missed the concept of a sealed injection channel with a slot and raised sides to contain the wave. Sorry erica.

On the paddles, I think their design will also need to take the reversal wave into effect. Maybe raised curved tops with horizontal edges that create downward pressure.

JamesHolt
08/15/2015, 07:28 PM
most are screw driven, so I don't know how fast these can be... or how much power they can deliver.
Think CNC they are screw driven (basically) and can move faster than you can see

herring_fish
08/15/2015, 07:36 PM
...I see paddles or the joints to the carriage breaking way before the actual drive....
I agree. that is where it needs to be beefy. In the picture (at bottom) that I am re-posting(from #113), you can see that the longer the paddle is (see big red arrow), the more it wants to rotate and that makes it push up on one side and down on the other(see the little red arrows).

This is something like what I had in mind. Notice that there are wheels on the top and bottom to take the stresses. Also there are rollers on the inside at both sides and both ends.

http://cdn.rigwheels.com/photo/RailDolly-2X.jpg

Now I offer this picture for a "go by" if you wanted to build two carriages your self. I would go with round tubes, not square but you get the idea.

http://www.igus.com/contentData/wpck/images/us_en/1_2/drylin-w-closeup.jpg Igus System

I have wheels drawn in below but you could also use ball bearing carriages but don't use Igus style carriages. It uses great space age, low friction, plastic. They work great for other applications. I use them but not for this. Stick with wheels or ball bearings. That my be a little more money but that is one of the places that the stress will be.

If your budget can handle the Cadillac ball bearing carriage, you can get the seller to spec out what you need. I would probably build my own if I could.

http://asaherring.com/reef/hardware/BafflePump.jpg

herring_fish
08/15/2015, 07:45 PM
So the front glass of the display is 54 inches? The baffles are 9 inches apart and a total stroke, in the back, of 36 inches and a displacement of 18 inches in the display? ...and 6 cycles per second?

Gorgok
08/15/2015, 09:04 PM
Think CNC they are screw driven (basically) and can move faster than you can see

I think those that really can haul are screw and ball drives, which isn't quite the same as just a screw drive... though i didn't see if these had screw and ball drives as well. Still they can be really fast with enough power.


That roller carriage is really easy to build. A pair of cheap rollerblades would get you enough wheels for probably less than you can buy the wheels for. The shaft size is a standard, you just need to get some bolts with a shank that size and thread a plate for them. Optionally include some adjustment standoffs for the bottom side and you can grip your rails with perfection.

If you want to get really fancy instead of the 'standard' size wheels get some goalie wheels, which are smaller so the contraption takes up less space. I do think having urethane wheels is better than straight bearings or something for this application though as you will hear it moving with metal to metal contact much more than with rubber on metal.

karimwassef
08/15/2015, 11:15 PM
Thanks guys. Some things I DIY. Others I choose to assemble based on higher quality off the shelf parts.

The stresses here are likely outside of my comfort zone for a DIY.

It's putting the cart before the horse though. Before looking at the carriage and drive, I want to confirm the flow meets the requirement and the overall design is small enough relative to the display space. Then, I can determine the stresses on the paddle joints and the power needed to drive the carriage. That's why I need to complete the CFD analysis.

herring_fish
08/15/2015, 11:33 PM
So the front glass of the display is 54 inches? The baffles are 9 inches apart and a total stroke, in the back, of 36 inches and a displacement of 18 inches in the display? ...and 6 cycles per second?

So is this roughly what you want to build? Additionally, is it 24 inches tall and about 3,000 pounds?

karimwassef
08/15/2015, 11:44 PM
Scaled and completely covered except for display and overflow. I think this is a reasonable balanced size

<a href="http://s1062.photobucket.com/user/karimwassef/media/1_zpsyhu2toge.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/1_zpsyhu2toge.jpg" border="0" alt=" photo 1_zpsyhu2toge.jpg"/></a>

still a little wasteful to dedicate 2 x 150 gal = 300 gal to the curved sides and 2 x 22 gal = 44 gal on the linear ends... 344 gal to curve.

~910gal

360 gal display (40% of total)
135 gal to channel + 345 gal curve = 480 gal (52%) ... wow
70 gal overflow (8%)

The front is 8' = 96in long. The ends add another 1' + 3.5' for a total of 13.5' tank.

Yes, the height is 24".

karimwassef
08/16/2015, 01:46 PM
Here is the desired design.

I think this is practically implementable and within some reasonable cost constraints.

It starts with a standard glass tank built at 10' x 4.5' x 2' (I don't like acrylic tanks. It was my biggest problem with the circular tank.)

The mechanism is essentially an acrylic construction inside the glass. The pieces are not glued to the tank (acrylic doesn't bond to glass), but think of it as an acrylic tank and mechanism inside the glass tank.

<a href="http://s1062.photobucket.com/user/karimwassef/media/1_zpszxx5ajyn.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/1_zpszxx5ajyn.jpg" border="0" alt=" photo 1_zpszxx5ajyn.jpg"/></a>

karimwassef
08/16/2015, 01:48 PM
I'll work up the 3D model. Still trying to find a simple free 2D CFD software to analyze it.

karimwassef
08/16/2015, 07:00 PM
Tried drawing it up, but the 6" overflow won't work. Not enough room for the bulkheads.

This is the current view at 5' x 10'

<a href="http://s1062.photobucket.com/user/karimwassef/media/1_zpsga7km8vj.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/1_zpsga7km8vj.jpg" border="0" alt=" photo 1_zpsga7km8vj.jpg"/></a>

Top left is the assembled system.
Top middle removes the water.
Top right is the glass tank only with the overflow.
Bottom left is the acrylic section with PVC round corners and the injection mechanism. This view also has the high top to contain splashes and surface waves around the paddles.
Bottom middle and right are the acrylic only views.

karimwassef
08/16/2015, 07:00 PM
With dimensions

<a href="http://s1062.photobucket.com/user/karimwassef/media/2_zpss4gt47lm.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/2_zpss4gt47lm.jpg" border="0" alt=" photo 2_zpss4gt47lm.jpg"/></a>

karimwassef
08/16/2015, 07:01 PM
Close up

<a href="http://s1062.photobucket.com/user/karimwassef/media/1_zpsevovedqs.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/1_zpsevovedqs.jpg" border="0" alt=" photo 1_zpsevovedqs.jpg"/></a>

The corners are made of 6" PVC pipe cut against the edge and mounted after the acrylic is assembled.

The high top is like a second little acrylic tank that is screwed in place into the top of the main acrylic section.

So far, it seems viable. What do you think?

herring_fish
08/16/2015, 09:38 PM
Wow!

karimwassef
08/16/2015, 11:36 PM
The carriage needs to move at 1ft/s for 6 seconds covering 6ft. Back of the envelope~ power needed to move the water is 400W. That's assuming lossless power transfer.

I have no feel for the efficiency of these kinds of drives.

karimwassef
08/17/2015, 12:42 AM
Oops recalc. Make that 2100W (damn back of the envelope didn't do units)

That moving a cross-section of 11.5" x 20" a distance of 72" in 6s, continuously.

It doesn't include losses which means it's too low.
It also doesn't include the fact that the velocity profile is sinusoidal with 1ft/s being the peak velocity amplitude. So the loss calculated is too high. :)

ericarenee
08/17/2015, 09:17 AM
It looks great .

One Question.. The 8 1/2 inch area after before the display area might need to have short baffles between the ones that are there say 7 inches long. to keep the water moving in channels all why to the plate.... Thou not sure 8 inches is enough to change the water force...

herring_fish
08/17/2015, 02:27 PM
OK I have to see if I am getting it right. Often, I am at work when reading the so I don’t concentrate on it enough to get everything right but…
LOL ….that hasn’t stopped me from making suggestions.

1. Have you changed the scope to get 6 feet of displacement in the back, at 3 to 1 ratio, to get 2 feet of displacement in the display tank, not 4 inches? Or have I read something earlier or now in my typical dyslexic way?

2. Why do you take up that rectangular area that has the 10” dimension in it? Could you take that back so that the side areas (that go from back to front) could be the same width as the back area? It looks like this area pinches down to limit flow. Am I just not looking at it right.

3. Also, can you heat and bend acrylic to use in the corners of the side baffles instead of using PVC? It looks like the back sides of the corners are sharp to disrupt laminar flow. The workmanship would not have to be pristine.

4. The three paddles are just being shown at both ends of the stroke? There is only one set, right?

Finally, (and this is not a rhetorical question. I really don’t know.) Am I right in thinking that when you move one part of the tank water, you are moving it all so you have to calculate for that?

Gorgok
08/17/2015, 03:48 PM
Finally, (and this is not a rhetorical question. I really don’t know.) Am I right in thinking that when you move one part of the tank water, you are moving it all so you have to calculate for that?

That would probably be true in a sealed system. But when paddling in the ocean you aren't moving the whole thing or oars would not be very effective =P. I imagine there are enough paths to dissipate the energy of the paddles that you don't have to account for most of the water in this as well. Probably more so than in the ocean though, as it is being channeled.

karimwassef
08/17/2015, 04:11 PM
It looks great .

One Question.. The 8 1/2 inch area after before the display area might need to have short baffles between the ones that are there say 7 inches long. to keep the water moving in channels all why to the plate.... Thou not sure 8 inches is enough to change the water force...

Agreed. There's plenty of design variables still in play. I think secondary baffles will likely be needed.

karimwassef
08/17/2015, 04:19 PM
1. Have you changed the scope to get 6 feet of displacement in the back, at 3 to 1 ratio, to get 2 feet of displacement in the display tank, not 4 inches? Or have I read something earlier or now in my typical dyslexic way?

The channel is 1ft, the display is 3ft. So 3:1 x. The display flow is 4in/s, so the channel is 12in/s.


2. Why do you take up that rectangular area that has the 10” dimension in it? Could you take that back so that the side areas (that go from back to front) could be the same width as the back area? It looks like this area pinches down to limit flow. Am I just not looking at it right.

That's the overflow. If not here, then where?


3. Also, can you heat and bend acrylic to use in the corners of the side baffles instead of using PVC? It looks like the back sides of the corners are sharp to disrupt laminar flow. The workmanship would not have to be pristine.

I don't have that competency. It has to bend and still be perfectly flat on the top and bottom.


4. The three paddles are just being shown at both ends of the stroke? There is only one set, right?

Yes.

Finally, (and this is not a rhetorical question. I really don’t know.) Am I right in thinking that when you move one part of the tank water, you are moving it all so you have to calculate for that?

That's wishful thinking IMO. I've been looking at this using analytical approximations and the math of bulk water waves is not easy. Especially because we're driving it over and over. Without a CFD model, I can't predict it meaningfully.

karimwassef
08/17/2015, 04:25 PM
That would probably be true in a sealed system. But when paddling in the ocean you aren't moving the whole thing or oars would not be very effective =P. I imagine there are enough paths to dissipate the energy of the paddles that you don't have to account for most of the water in this as well. Probably more so than in the ocean though, as it is being channeled.

Sealing this mechanism in an acrylic tube was the key to creating a syringe like effect where you push and it moves forward, not up. I'm still concerned that the waves may be so high that the shaft + slot assembly may also need to be sealed (or raised).

The output will look like a bulk wave push, I think. Predicting the actual flow of the 360gal in the middle is harder. I need an analytical model or a CFD tool to predict it.

Turns out that pushing water and having it go where you want in an open top is not a trivial problem...

herring_fish
08/17/2015, 04:56 PM
1. Have you changed the scope to get 6 feet of displacement in the back, at 3 to 1 ratio, to get 2 feet of displacement in the display tank, not 4 inches?

I’m just talking about the distance that the water moves past a given coral in one direction total not inches per second. You say that I have read you correctly on the 3:1 so if you move the paddles 6 feet, then the water in the display would move 2, right? I thought you were talking about 4 or 5 inches total, not two feet. Not that is a bad thing at all. I’m just trying to pin down the scope.

2. Why do you take up that rectangular area that has the 10” dimension in it? Could you take that back so that the side areas (that go from back to front) could be the same width as the back area? It looks like this area pinches down to limit flow. Am I just not looking at it right.

“That's the overflow. If not here, then where?”

I may still be misunderstanding, sorry. I’m not talking about the dark purplish area, just the stuff in the little rectangles, at the ends where the dimension actually is.

Finally, (and this is not a rhetorical question. I really don’t know.) Am I right in thinking that when you move one part of the tank water, you are moving it all so you have to calculate for that?

“That's wishful thinking IMO.”

Undoubtedly, you are correct completely but if it were truly laminar, without big waves or in a tube, it might happen in a perfect world and if it did, that would be a worst case. Again, I am just looking at scope.

If movement is dissipated or transferred out of phase, then you might be moving 200 pounds. If it all moves then you may be talking a ton and a half.

karimwassef
08/17/2015, 06:12 PM
In terms of travel distance - you're right. The 6ft of travel is not necessary for a 12" channel. The paddle distance needed is only 15.3in to get to 4in/s. That would translate to 15.3/3 ~ 5in in the display. This is because the injection velocity and position profiles are sinusoidal. That will reduce the power needed (I think). I need to go back to redo the back of the envelope with a shorter travel and sinusoidal velocity.

<a href="http://s1062.photobucket.com/user/karimwassef/media/1_zpswk0hhpeb.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/1_zpswk0hhpeb.jpg" border="0" alt=" photo 1_zpswk0hhpeb.jpg"/></a>

The little rectangles on either side of the overflow are there to channel the flow in the bottom baffle. If you remove that area, that baffle would have no travel after the turn. There would be no distance to align the flow.

I already think that the little 6" of travel is too small to align the flow. Taking the box out would leave a chaotic output after a turn. The other channels have different distances. Top ~ 12". Second is 10". Third is 8". Fourth is 6". I can't see an alternate solution right now, but let's keep thinking.

The volume being moved in each 6 second cycle is ~15in x 12in x 20in. That's 16 gal for each 6 seconds. The main tank sees 5in x 36in x 20in = 16gal. That's 130lbs per 6 second stroke.

This might mean that the injection channel can be reduced to 3" and then span the full 6ft of travel. The injection channel inlets are 2.5" wide now and the side channels are only 1" wide. If we cut back the width of the main injection channel, the inlets would have to shrink commensurately. That probably limits the injection channel to 5" at the smallest... more design variables :D.

I'll redo the power loss before we iterate.

Fiziksgeek
08/17/2015, 06:39 PM
I only skimmed the thread, but what you are trying to do reminds me of gyre flow. Here is a reference from 2007 (http://www.advancedaquarist.com/2007/1/aafeature)

karimwassef
08/17/2015, 07:47 PM
Excellent article! Thanks Fiziks and welcome.

Yes, the concept is similar to a gyre but with a few differences:

1. The flow is not channeled into a narrow cross-section using dividers in the tank. The idea is to look natural but still create the same effect.

2. The flow is spread across the full and very wide cross-section (3ft) of the tank. So the entire tank water needs to flow like a gyre.

3. The flow alternates frequently. The gyres described in the article flow in one rotation for a long time, then alternate.

The flow description and benefits are accurate though.

It also highlights some basics that we need to incorporate...

1. Removing more surface waves by creating a deeper underwater channel.

2. Raising the flow from the bottom to avoid blowing sand storms.

karimwassef
08/17/2015, 11:24 PM
In terms of travel distance - you're right. The 6ft of travel is not necessary for a 12" channel. The paddle distance needed is only 15.3in to get to 4in/s. That would translate to 15.3/3 ~ 5in in the display. This is because the injection velocity and position profiles are sinusoidal. That will reduce the power needed (I think). I need to go back to redo the back of the envelope with a shorter travel and sinusoidal velocity.

I really shouldn't do math when I'm tired :)

The 4in/s is the peak velocity in the display.
That means that the peak velocity is 12in/s in the channel.
Using the same math above, but with the actual desired peak speed, the result is ~ 45in in each direction in the channel. Still not all 6', but a pretty hefty swing at 12in/s peak velocity.

That would mean that the travel in the display is 15in in each direction ... at a peak speed of 4in/s.

The average power is about 1000W.

karimwassef
08/18/2015, 10:28 PM
Here's what I think will happen. This is just a zero order 1D analytical calculation.

<iframe width="560" height="315" src="https://www.youtube.com/embed/nHsqQXOUlwU" frameborder="0" allowfullscreen></iframe>

herring_fish
08/19/2015, 09:06 AM
It’s looking good at 12 seconds. What are all of the colors? I get most but not all of them. Would you be able to simulate the height of the surface wave in the DT?

karimwassef
08/19/2015, 02:06 PM
Which colors? In the graphs or on the tank layout?

karimwassef
08/19/2015, 02:11 PM
This is a zero order model, so not anywhere near modeling the trochoidal waveforms that could result at the outlet. I've given up on the modeling for now. I'll build a small 24:1 model (2.5" x 5") and use a linear actuator with a little control board to control acceleration.

The properties of the fluid would need to be mapped so that it simulates what a large body of water would do. So, I can't run water... I would need to make a less viscous material (I think). I have to go back to those old scaling rules to get it right.

herring_fish
08/19/2015, 03:31 PM
Dude,

Where did you learn this stuff!?! Very cool!

Oh I'm talking about the colors of the simulation. When I went to school, they didn't have this stuff on the net.

karimwassef
08/19/2015, 09:41 PM
It's just excel.

The colors on the graph -
Blue is velocity
Red is position
Green is acceleration (also Force)
Purple is lossless power

karimwassef
08/19/2015, 09:43 PM
Looks like I would need to use acetone on a scaled down model to emulate the big tank. I can't scale the wall thicknesses, but I just need a proof of concept.

I think acetone melts acrylic though?

herring_fish
08/19/2015, 09:45 PM
Excel? We didn't have that. I had a professor that won't even let us use a calculator.

karimwassef
08/20/2015, 12:12 AM
It's a spreadsheet tool from Microsoft.

So... Before I mock one up. Any other ideas?

I'm going to try one with tiny DC powerheads and another one with an actuated paddle.

Everyone think this is the best solution so far?

herring_fish
08/20/2015, 08:01 AM
Remember as it relates to ideas: Volume not quality

This is another idea that won’t be adopted as is but my spur something that might actually work. I hope that you will be entertained and not annoyed.

If the sides represent a throttling pinch point, could you angle the outlets to open the side channels? This is a VERY rough pic of what I am talking about but CAD could be used to draw out smooth transitions and enough straight area at the outlets to give the flow direction that you want while giving the maximum cross section so that the paddles are not pushing against the choke point.

http://asaherring.com/reef/hardware/ThrottleBody.jpg

karimwassef
08/20/2015, 12:01 PM
I could also just open up the sides. I wanted to limit the "wasted" space on the sides to 12" on each side.

It also needs enough travel distance in the final direction of flow to make it laminar. I can't have a turn 1" before the exit and expect it to be laminar unless the flow rate is very very low.

herring_fish
08/20/2015, 12:08 PM
As long as the side equals the back chamber in total cross sectional volume, you will be OK. In that case, it wouldn’t be a pinch point. It just looked that way.

If so ..my mistake.

karimwassef
08/20/2015, 01:01 PM
double post

karimwassef
08/20/2015, 01:15 PM
<a href="http://s1062.photobucket.com/user/karimwassef/media/1_zpsntsnc4h9.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/1_zpsntsnc4h9.jpg" border="0" alt=" photo 1_zpsntsnc4h9.jpg"/></a>

They're the same total width 11.5"

I didn't want to take more that 1ft on either side of the 8ft display for the mechanism.

But I need to keep at least a 5.5" straight run on the bottom channel to guide the flow in that direction.

The walls are 0.5" thick

So each channel can only be 1" wide.

karimwassef
08/21/2015, 12:10 PM
Gone back and forth on scale and building material... cost, ease, etc... of the model build.

Here's my conclusion - I need a carpenter.

The scale is 1:2.5 = 2' x 4' wood coated with sealant...

My sump is a 150gal epoxy plywood, so I've done this kind of thing before.

This one just needs to survive for a week at most.

Maybe a thin acrylic top to see in.

So... Any carpenters?

karimwassef
08/21/2015, 03:42 PM
Makes me wish I had a router so I can create 1/4" grooves for the baffles to fit into. Going to be hard to create a strong bond with vertically mounted 1/4" plywood strips otherwise.

JamesHolt
08/21/2015, 05:04 PM
Finally, (and this is not a rhetorical question. I really don’t know.) Am I right in thinking that when you move one part of the tank water, you are moving it all so you have to calculate for that?

This will be a yes or no answer depending on how it is done..
If you are using a pump, the tank water moves for free (pump has to pull from somewhere). Just need to calculate for inertia of tank water..

With the paddles, you would just need to calaulate overcoming the inertia,resistance to being directed, and the momentum when you change directions.. :hmm4:

I dont think the idea with the paddles hanging down will last for long, it being offset like that and the forces on it will destroy linear bearings in short order..

The best bet for success with the paddles would be a rodless cylinder that can be submerged in SW.
That way it can push/pull from the center of the paddles.. There are also enclosed ballscrews setups that work the same way..

Second concern for the paddle setup as being shown is grease..
It will have to be lubricated and that lubrication will fall into the water, also when the bearing fails it will throw little balls and grease everywhere..

The idea of using wheels/cam followers will also need lubrication and be self destructive.. Plus the concern of broken parts/grease falling in the water also..

Since the calcs have be done for how big of a chunk of water needs to be moved, we/someone should be able to come up with a externally mounted driver and a piston chamber to meet the needs and not endanger the tank or its critters..

Dont take my comments as me being arrogant or an ***, I have been in industrial maintenance for 30 years and I tend to just blurt stuff out.. :spin3:

karimwassef
08/21/2015, 05:15 PM
Thanks James.

I think a more robust solution is always better and the fewer the parts that need to be maintained, the better.

Since the displacement is only 4ft, it may be possible to do it with a linear actuator or driver. As long as I can control the acceleration/velocity, then it should work.

I've discussed the question of how much force is required with a couple of mechanical engineers. They both agreed that it would be a function of the displaced volume only. One of them came up with the conceptual idea of sizing the width of the display tank as infinite (looking as the limit). In that case, the force would only move the water it displaces since the water returning from the other end would never actually come back. In that case, is the force infinite? No... so the force cannot be a function of the total volume.

JamesHolt
08/21/2015, 05:25 PM
4ft, is that the total distance the water needs to move or how much you need to put in one side..
Also, gallon wise how much needs to be moved and how fast in seconds
If it is total we would need to push 2ft while pulling 2ft on the other side..
Either way a 2ft or 4ft push wouldnt be to hard to do, either pneumatic or a small Hydraulic power pak would work..
Could even use a screw drive to keep it simple..
Sorry, I never got into the engineering side more than just casual design, so alot of these formulas just lose me. I tend to base my stuff on my past experiences and failures..

JamesHolt
08/21/2015, 05:53 PM
http://www.reefcentral.com/forums/picture.php?albumid=10209&pictureid=71264

Something like this, picture is big, they now are blocking me from using photobucket(at work)

karimwassef
08/21/2015, 07:05 PM
Are you talking about putting the injection chamber under the tank? Looks like it's under the stand?

herring_fish
08/21/2015, 07:06 PM
If you have a piston below the tank, you will fighting seal failure. This is what has killed many a wave project. I think that you are closer with the last one.

karimwassef
08/21/2015, 07:20 PM
Here's the design details

<a href="http://s1062.photobucket.com/user/karimwassef/media/1_zpsag2zkbak.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/1_zpsag2zkbak.jpg" border="0" alt=" photo 1_zpsag2zkbak.jpg"/></a>

and here's the wooden model dimensions in 1/2" and 1/4" plywood with an acrylic top

<a href="http://s1062.photobucket.com/user/karimwassef/media/2_zpsnyshmx5t.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/2_zpsnyshmx5t.jpg" border="0" alt=" photo 2_zpsnyshmx5t.jpg"/></a>

karimwassef
08/21/2015, 07:25 PM
I also worked out the cost of doing it with embedded DC powerheads, 16 of them in the back channel with 8 in each direction. The channel is 12" x 20". The powerhead outlet only needs about 4" x 4", so this is actually viable...

Cost is $1840 and the peak power is only 320W (since only 8 are actually on at any one time). They do need to be enclosed in the acrylic mechanism though.

I haven't worked out the scaled model design variables - scaled speed, etc...

JamesHolt
08/21/2015, 07:40 PM
If you have a piston below the tank, you will fighting seal failure. This is what has killed many a wave project. I think that you are closer with the last one.

If you use the correct seal setup, it wont matter where it is located..
You would need a stacked setup on the piston..
At a minimum,, Cup seal, o-ring,o-ring,teflon slider, teflon slider,o-ring,o-ring,Cup seal

That way the cup does the work of pushing , the two o-rings do support and sealing, the sliders hold everything centered...

JamesHolt
08/21/2015, 07:55 PM
You could also do a one sided arrangement and push one way into an expansion chamber..
Push, hold, and let it fall back...
Would have to be a sealed top on the push, and DT...

herring_fish
08/21/2015, 08:23 PM
Those seals work in US submarines but public displays have not had very good luck. They don’t have US Navy budgets or maintenance schedules but they have more access to money than I do.

I agree that YOU could probably spec some stuff that would work but this has been done several times and there is always a fly in the ointment. Given several design revisions you could work out the kinks but seals are a pain. Karimwassef has better skills than I do but if you lived in his town, I think that he would have better luck trying that one.

Burlington? …Shoot, you live closer to me than him. Maybe, I could get you to give me some practical advice from time to time. I could sure use it. :lol:

karimwassef
08/21/2015, 08:31 PM
Going back to Fiziks' comment on gyre tanks and the 3rd setup in this article: http://www.advancedaquarist.com/2007/1/aafeature

Back in 2007, the DC propeller powerheads we have today didn't exist. They also didn't use open inlets for massive flow. So adapting the concept to an alternating massive volume laminar flow wouldn't have been practical.

But the design is actually very similar to what we have here. It looks like there's a hidden section behind the overflow covered by a black plastic grate. The powerhead there pushes the water into an oval loop (gyre) that crosses the DT and then back into the hidden section. It alternates over hours, not seconds.

Having done the calculation for the RW20s and considering putting them into a sealed box, I think this can be made in even less space than the paddle. The key is the closed loop in the back and the two sets of massive, opposing, and phase synchronized propeller pumps. Follow that with a laminarizing box... And I think that does it.

karimwassef
08/21/2015, 08:34 PM
I'll still make a wooden box, but a simpler one now.

karimwassef
08/21/2015, 08:35 PM
I know it's frustrating to go paddle-pump-paddle-pump... But when you bring up seals and leaks, I go back to the safety of pumps. :D

JamesHolt
08/21/2015, 09:12 PM
What causes the seals to fail...
I put an air-over-hydro cylinder on a coolant filter system..(speced with this same arrangement, teflon seals and orings, stainless cylinder tube)
regulated air on one side, nasty coolant on the other (pressure input), this balances a manual valve that controls coolant flow to two very large machines. It constantly cycles back and forth..
There has never been a rebuild or any leaks, and this is still in use 13 years later..

herring_fish
08/21/2015, 09:27 PM
Can that be scaled down?

Gorgok
08/21/2015, 10:26 PM
I know it's frustrating to go paddle-pump-paddle-pump... But when you bring up seals and leaks, I go back to the safety of pumps. :D


With pump outlets/powerheads you can gain some flow just placing them in ideal locations i think. Putting typical powerheads in the middle of the back loop will be worst case i think, as they end up fighting their own wake to generate more flow. But powerheads or closed loop outlets them right by the entrance of the return side of their respective loops the water they work on may get pulled further along like in a venturi. Closed loop outlets could also be angled in along the straight back for the same effect i think, just like fuel injection on an intake manifold.

Powerheads may be less ideal than a monster of a closed loop as well, as its harder to make flow past a typical powerhead laminar...

Typical powerhead design is actually lacking for this application as you are really after a propeller more so than a fan. A trolling motor is better suited to this idea... You could have those in the middle back and the little disruption to the flow it creates won't matter one bit the the time it curves back around the front. If you sized it right you could even turn it around when flow changes like an azipod... Or cobble up a Z drive unit out of something even slimmer and stick a motor out of the tank to drive it. Blended fish will always be on the menu though.

karimwassef
08/21/2015, 10:37 PM
Going through the propeller ideas now

JamesHolt
08/21/2015, 11:27 PM
there is a "powerhead" you use to keep water clear around docks,, cant remember what it is called